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Author Topic: Any word on Div. C Wright Stuff planes for 2018-2019 season?  (Read 2029 times)
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Little-Acorn
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« on: July 30, 2018, 10:39:06 AM »

From the SOSI proceedings, it looks like Wright Stuff will move from Div. B (Middle Schools) to Div. C (High Schools) this coming season.

I know the official release comes after Labor Day. But has anybody heard any rumors about how big and/or light the planes can be according to the (coming) rules?

Enquiring minds want to know!
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JasperKota
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« Reply #1 on: September 03, 2018, 09:51:26 PM »

Seems that rules are out a bit early! https://store.soinc.org/us/page/manuals?resetallfilter=1 Wright Stuff rules are in the Division C manual  Grin It seems differences from recent years are smaller wingspan and horizontal stab, heavier, no motor mass limit, and also no propeller length limit.  The bonus remains the same, a black wingtip, and also the extra bonus for winding and setting up quickly.

I think this is going to be an interesting year, maybe with a lot more experimentation with motors. I'm also a bit interested with experimenting in making my own propellers for the first time, though if it'll be necessary, given that my team doesn't go beyond the state level, I'm not so sure.
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Olbill
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« Reply #2 on: September 03, 2018, 10:22:26 PM »

The preliminary rules didn't have a limit on stab size. Has that changed?
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leop
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« Reply #3 on: September 04, 2018, 08:13:12 AM »

The wing must be the "single largest surface."  This limits the stab to having less projected area than the wing.  There appear to be no other stab restrictions.

LeoP
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cglynn
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« Reply #4 on: September 04, 2018, 12:37:19 PM »

Is anyone else thinking about a tandem or near tandem design for this year's contest? 

And with no motor mass limit or prop limit, these things could be getting dangerously close to becoming serious indoor models.
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Maxout
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« Reply #5 on: September 04, 2018, 01:05:10 PM »

Is anyone else thinking about a tandem or near tandem design for this year's contest? 

In development already

And with no motor mass limit or prop limit, these things could be getting dangerously close to becoming serious indoor models.

Sheer bedlam. In all seriousness, this will not end well. Mark my words, next year's rules set will be a massive pendulum swing in the other direction, probably to a similar level of epic failure.
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calgoddard
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« Reply #6 on: September 04, 2018, 03:09:03 PM »

Josh, as you are aware, I tried, in vain, to solve most of the problems with the Wright Stuff event. Others may not know this so I am posting this information.

A couple of years ago my daughter and I wrote rules for an event called Rubber Powered Airplane (RPA).  It was run successfully as a trial event at the SciOly SoCal State finals held at Caltech in 2017.

The committee at the National SciOly organization did not adopt RPA as a flying event in lieu of WS.

Here is a link to a topic on the HPA topic with all the details of the RPA event.

http://www.hippocketaeronautics.com/hpa_forum/index.php?topic=21883.0

At least the committee adopted parts of my proposed RPA event.  It got rid of the ridiculous weight limit on the rubber motor in the WS event.  Time in the air can be limited other ways.  Ditto for the limit on the diameter of the prop. Let students experiment with these variables and relieve the ES from the burden of weighing rubber motors and measuring the dimensions of various components of the airplane. There is no reason in the WS event to limit the configuration of the airplane to a monoplane.  This restriction simply stifles creativity.
« Last Edit: September 04, 2018, 03:43:40 PM by calgoddard » Logged
calgoddard
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« Reply #7 on: September 04, 2018, 03:28:43 PM »

See my last post.

The link to the rules for the RPA event no longer works.

I will figure out a way to post them here.

The rules for the RPA event were jointly written by me and my daughter, who was a multiple gold medal winner in WS at both the regional and state level.



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calgoddard
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« Reply #8 on: September 04, 2018, 03:30:55 PM »

RUBBER POWERED AIRPLANE

1.   DESCRIPTION:  Prior to the tournament teams will design, construct, and test free-flight rubber-powered airplanes to achieve maximum time aloft.

    A TEAM OF UP TO: 2      IMPOUND:  None      TIME: 8 minutes

2.   EVENT PARAMETERS:
a.   Teams may bring up to two airplanes, any tools, and their flight log.
b.   The Event Supervisor must provide all measurement materials and timing devices.

3.   CONSTRUCTION PARAMETERS:
a.   Airplanes may be constructed from student design, published plans, and/or commercial kits. Kits must not contain any pre-glued joints or pre-covered surfaces.
b.   Any materials except Boron filaments may be used in construction of the airplanes.
c.   The total mass of each airplane, excluding the rubber motor, must be at least 5.0 g.
d.   Each airplane must be built to fit into a FedEx Large Box® (L1: rectangular and shallow in shape), advertised to have interior dimensions of 12-3/8 x 3 x 17-1/2 inches (approximately 31.4 x 7.6 x 44.4 cm), while in flight configuration. 
e.   Each airplane may have any air frame configuration (tractor, pusher, canard, bi-plane, twin propellers, etc.) and need not resemble a conventional “airplane” shape.
f.   Airplanes may only be propelled in-flight through the release of mechanical energy stored in wound rubber motors.  No other energy source may be used to keep the airplane aloft.
g.   Propeller assemblies may be student-built or purchased.  Variable pitch propellers that include mechanisms to actively change the blade diameter or angle must not be used.  There are no restrictions on the number, size, or construction of each propeller assembly.
h.   Rubber motor(s) may include one or more strands or loops of rubber.  Attachments such as O-rings and lubrication are permitted.  There are no other restrictions on the dimensions, weight, or number of rubber motors that power the airplane(s).
i.   The airplane(s) must be labeled with student’s school name and team number.
j.   Students must be able to answer questions regarding the design, construction, and operation of their airplane(s) consistent with the Building Policy found at ww.soinc.org.
   
4.   THE COMPETITION:
a.   The event must be held indoors.  Tournament officials must announce the dimensions of the flying site (approximate length, width and flyable height to the lowest ceiling obstruction) in advance of the competition.  Tournament officials and the Event Supervisor are urged to take steps in advance of and on the day of the competition to turn off the HVAC. Air currents should be minimized by keeping doors and windows closed while airplanes are in flight.
b.   The competition area shall be cordoned off.  Once students enter the competition area to compete they cannot leave the competition area until they are finished competing.  They must not receive outside assistance, materials, or communication.  Spectators must remain outside the competition area.
c.   Students must present their airplane(s) and flight log for inspection before their 8-minute Flight Period.  The Event Supervisor will notify the student if the airplane(s) or flight log are not in compliance with the rules and what penalties, if any, will be incurred as a result.
d.   The flight log must include data for at least 10 test flights with at least the following parameters: rubber motor size, approximate number of winds at launch, and flight duration.  Additional parameters are encouraged but not required in the flight log.
e.   Size conformance for the airplane(s) will be demonstrated using the following procedure with a FedEx Large Box® provided by the Event Supervisor:
i.   The student will load the airplane (with or without propeller assemblies and rubber motor(s) installed) into a provided box through the standard open end without causing any significant deformation of the airplane.
ii.   While the student is holding the box, the Event Supervisor or a designated volunteer will pass a ruler along the face of open end of box.  The ruler must not contact the airplane.
iii.   Next, the student will tip or fully invert the box which must cause the airplane to slide out of the box under its own weight.  Pulling on the airplane, shaking the box, or tapping on the box must not be necessary to remove the airplane from the box and will not be permitted. 
f.   To account for potential small variations in the manufacture of the FedEx Large Box®, the Event Supervisor will supply at least two boxes to be used at check-in.  An airplane that passes the size conformance procedure for at least one of the provided boxes will be considered acceptable.  An airplane that cannot pass the size conformance procedure for any of the boxes provided by the Event Supervisor will violate the rules.
g.   A self-check station, within the competition area, may be made available to students for checking their airplanes prior to a team’s official check-in with the Event Supervisor and/or    the designated volunteer(s).  A FedEx Large Box® shall be located at the self-check station.
h.   Each team will be given an official 8-minute Flight Period, starting when their first official flight begins. During the Flight Period, students may conduct practice flights and up to 2 official flights.  All flights will be assumed to be official flights unless clearly declared as practice flights to the Event Supervisor before the flight.  Students may also repair and adjust their airplane(s) during this time.
i.   At the discretion of the Event Supervisor multiple official flights may occur simultaneously.  Teams may elect a re-flight in the unlikely event of a collision with another airplane. Practice flights may occur throughout the competition but must yield to official flights. No practice flights will occur in the final half-hour of the competition except for teams that declare a practice flight during their Flight Period. The Flight Period shall be extended at the discretion of the Event Supervisor to accommodate any re-flight necessitated by a collision with another airplane or to avoid conflicting simultaneous launches.
j.   Students must launch their airplanes(s) by hand while standing or kneeling at floor level.  No external equipment may be used in contact with the airplane during the launch.  Students may not steer their airplanes in flight.
k.   An official flight time shall be the time aloft, beginning when the airplane leaves the student’s hands and ending when any part of the airplane hits the floor, the airplane becomes lodged on an obstruction (such as a beam, light fixture or basketball backboard), or the Event Supervisor otherwise determines the flight to be over.
l.   Event Supervisors are strongly encouraged to utilize three independent timers on flights.  The median of the three times should be recorded as the official flight time, in total seconds and hundredths of seconds (Ex: 147.21 seconds).
m.   The Event Supervisor will verify the recorded official flight time(s) and any incurred penalties with the students.

5.   SCORING:   
a.   A team’s score is the duration of the team’s longest official flight, in total seconds and hundredths of seconds, reduced by any penalties.  Teams shall be ranked based on this score, with the highest score being the winner of the event.
b.   Ties shall be broken using the score calculated with the team’s second longest official flight.
c.   Teams with an incomplete flight log shall have 10% deducted from each official flight time.
d.   Teams with no flight log shall have 30% deducted from each official flight time.
e.   Teams that violate any rule(s) under CONSTRUCTION PARAMETERS or THE COMPETITION will be ranked behind all teams that do not violate any rules.
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ceandra
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« Reply #9 on: September 04, 2018, 03:36:34 PM »

This year certainly opens up a number of new variables, which will allow the students to explore the design space.

Several weeks ago we took some wings from 2016 (6cm x 40cm), put them on a motor stick with a large prop, and tested as a true tandem. The basic concept flew well after a few adjustments, and appears to be quite stable. As in prior years, the keys to success will focus more on the prop/rubber setup than on the design of the plane, given a reasonable design to start with. Only this year those variables are not as limited, allowing a wider range of testing.

While we build to the rules over the next few weeks, we'll use this tandem built from old parts to start getting gym experience. This year will not be won by last-minute builds! A big part of flying this old contraption will be to bound the rubber sizes of interest before I buy a box of rubber.

I know at least some of the usual kit builders are working on tandem or near-tandem designs with success. It would appear that we will have to make the stab slightly smaller in order to fit the rule, but that difference can be minuscule.

Looking forward to another fun year!

Chuck
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calgoddard
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« Reply #10 on: September 04, 2018, 03:42:12 PM »

Olbill has already proven the viability of the tandem configuration with his BILL'S A-6.  If I  am not mistaken, he used this model to set the AMA CAT 1, CAT 2, CAT 3 and CAT 4 records in the A-6 event.

ceandra - It's time for you to purchase a Harlan rubber stripper if you don't already have one.  Your post implies that you are going to purchase a box of rubber of a certain dimension.  It is pretty rare, in my experience, for any box of TSS rubber to have a width that is optimum for flying a particular indoor duration (aka "stick") model airplane.  Actually, I don't go by width of the rubber motor in serious competition.  I go by length and weight of the rubber motor.  As you probably know, the thickness of TSS rubber varies along its length and from batch to batch.  In addition, the rubber varies in density along its length.  Finally, it is not possible to strip rubber with a precision width over the entire length of a rubber motor due to the elastic nature of the rubber itself and mechanical limitations of the stripper and the feeding process.

When I first got into indoor flying about 15 years ago the late Cezar Banks cringed when he asked about the size of the rubber motor I was flying with and I told him the width of that rubber motor. He only wanted to hear about its length and weight.  Cezar finished 2nd multiple times in the world F1D championships.  Cezar was a brilliant engineer and he invented the variable pitch mechanism in F1D props that has been used for decades.  He is perhaps best known for the Banks Limited Penny Plane.    
« Last Edit: September 04, 2018, 04:02:55 PM by calgoddard » Logged
Little-Acorn
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« Reply #11 on: September 04, 2018, 04:04:13 PM »

At last, here are the Final Rules for Wright Stuff 2019 (Div. C). Direct copy/paste from the PDF. Formatting is slightly different, but all words, dimensions, times etc. are identical to the PDF.

Some significant differences from last season (Div. B) in aircraft design:
* Wing is 35cm x 7 cm (smaller than last season)
* Airframe min weight is 8 gr without rubber (higher than last season)
* NO dimensional or weight restrictions on prop, rubber or stabilizer

--------------------------------------------

WRIGHT STUFF
©2019-C39

Publishing of Wright Stuff Rules is, apparently, an infringement of their copyright terms.

The following link will take you to their web site where you can sign up, sign in and download the Rules PDF free of charge.

https://store.soinc.org/us/page/manuals?resetallfilter=1

Ratz
Forum Admin

--------------------------------------------

Ratz Edit: Removed the Rules. Added link to Science Olympiad - Wright Stuff page
« Last Edit: September 04, 2018, 06:24:48 PM by Ratz » Logged
ceandra
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« Reply #12 on: September 04, 2018, 04:53:00 PM »

Cal:

Yes, I have a Harlan stripper. Had previously borrowed a polish stripper, but upgraded to Harlan 1.5 years ago.

My point was whether I needed to get 1/8" or 3/32 as starting stock. With the small props we used the last two years, the end product was around 0.0375-0.042 g/in depending on prop, which is around 1/16", so I used 3/32" stock. With the larger props, it appears that we will be at or over 3/32", but I want to make sure we don't get real close to 1/8" before I buy, or I would need to go up to 3/16" as my starting stock.

So, yes, good point. Just making sure I get wide enough stock to start.

Chuck
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Olbill
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« Reply #13 on: September 04, 2018, 04:58:47 PM »

Rule 4G makes no sense. Why check in motors if there are no specs for motors?

If I'm able to go to Rantoul for the October contest I hope to take a model for testing.
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ILM Tarheel
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« Reply #14 on: September 04, 2018, 05:09:43 PM »

Olbill,

See the rules about scoring. The return of the motors to the contestants starts the "clock" for the bonus points. It has nothing to do with the motors themselves.

Jimmy J
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calgoddard
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« Reply #15 on: September 04, 2018, 05:32:07 PM »

ceandra -

My apologies.  I should have known from your intelligent posts that you already had a rubber stripper.

I can see the logic in waiting to see what width of TSS rubber to buy.  I am guessing that many coaches, designers and/or students will experiment with the 22.5 cm Ikra prop (1.8 grams). That's about 64% of the max wing span.

Limited Penny Planes (LPPs) fly with a max 12 inch diameter prop, which is about 66% of the max wing span.
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Little-Acorn
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« Reply #16 on: September 04, 2018, 06:11:10 PM »

The lack of any real restrictions on motor size and propeller size, opens up the possibility of really long or thick motors, and big props of course.

I'v built and tested a couple of planes conforming to the new rules, and tested all of the above on them. It would take weeks or months to test all possible combinations of course, but so far I've seen that big, thick (28" loop of 1/8" TSS rubber, homemade 8" diameter prop made from Ikara parts) tend to have so much torque at high winds, that the plane rolls over to the left like a dead whale. Put in a significant amount of right thrust to compensate, and it rolls over anyway, and then tries to climb sideways ("knife-edge" flight). So I've backed off to .093" or thinner, and it stays more level.

The tiny wing is what must keep the plane level (compensating for the motor torque rolling the plane to the left), as the prop slipstream corkscrews around the fuselage and hits the left wing at a higher angle of attack than the right. I'm wondering if the difference in left-wing left over right-wing lift might cause the left to stall out, since the wing is smaller but must carry more weight (8g plus the weight of the BIG motor).

Got a lot of refining to do, of course, but so far I'm less interested now, in really big motors.

One other interesting thing though, is that the lack of limits on rubber motors, can result in really long motor sticks with long medium-thickness motors. Propeller fin effect causes the usual instability problems when the wing is like 10" or more behind the prop. But one of my test planes is a canard (tailfirst, pusher), which flies beautifully, and has very few of the problems I get from tractor (propeller in front) planes. Both the stab and the wing lift while the CG keeps the plane statically stable, and the pusher prop also makes it more stable instead of less. Still got a lot of work to do, but I'm looking forward to seeing if I can get long flights out of the canard with its 28" motor loop.

Winding the canard up backward takes some getting used to.

Bye, I'm off to the gym....!   Grin
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ceandra
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« Reply #17 on: September 04, 2018, 06:40:08 PM »

With the stock Ikara (24cm) flaring prop, we were testing at around 0.075g/in rubber, which is larger than 3/32 (cut from 1/8" stock last year for heli class). We did not see any stability issues nor rolling in, granted the wing is slightly longer (40cm) than this year's rules. We'll probably try up to about 12" initially.

But, the pusher is definitely and interesting option.

Chuck
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Olbill
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« Reply #18 on: September 04, 2018, 11:06:12 PM »

The lack of any real restrictions on motor size and propeller size, opens up the possibility of really long or thick motors, and big props of course.

I'v built and tested a couple of planes conforming to the new rules, and tested all of the above on them. It would take weeks or months to test all possible combinations of course, but so far I've seen that big, thick (28" loop of 1/8" TSS rubber, homemade 8" diameter prop made from Ikara parts) tend to have so much torque at high winds, that the plane rolls over to the left like a dead whale. Put in a significant amount of right thrust to compensate, and it rolls over anyway, and then tries to climb sideways ("knife-edge" flight). So I've backed off to .093" or thinner, and it stays more level.

The tiny wing is what must keep the plane level (compensating for the motor torque rolling the plane to the left), as the prop slipstream corkscrews around the fuselage and hits the left wing at a higher angle of attack than the right. I'm wondering if the difference in left-wing left over right-wing lift might cause the left to stall out, since the wing is smaller but must carry more weight (8g plus the weight of the BIG motor).

Got a lot of refining to do, of course, but so far I'm less interested now, in really big motors.

One other interesting thing though, is that the lack of limits on rubber motors, can result in really long motor sticks with long medium-thickness motors. Propeller fin effect causes the usual instability problems when the wing is like 10" or more behind the prop. But one of my test planes is a canard (tailfirst, pusher), which flies beautifully, and has very few of the problems I get from tractor (propeller in front) planes. Both the stab and the wing lift while the CG keeps the plane statically stable, and the pusher prop also makes it more stable instead of less. Still got a lot of work to do, but I'm looking forward to seeing if I can get long flights out of the canard with its 28" motor loop.

Winding the canard up backward takes some getting used to.

Bye, I'm off to the gym....!   Grin

You definitely don't want right thrust in an indoor model.
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Little-Acorn
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« Reply #19 on: September 04, 2018, 11:17:37 PM »

You definitely don't want right thrust in an indoor model.

Right thrust saved us last season. Couldn't have won without it. Once we started using it, we started getting 2-minute flights.

See http://www.hippocketaeronautics.com/hpa_forum/index.php?topic=22721.msg224414;topicseen#msg224414
« Last Edit: September 04, 2018, 11:29:01 PM by Little-Acorn » Logged
Maxout
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« Reply #20 on: September 05, 2018, 11:16:42 AM »

I know at least some of the usual kit builders are working on tandem or near-tandem designs with success. It would appear that we will have to make the stab slightly smaller in order to fit the rule, but that difference can be minuscule.

I'm planning to be the newcomer to the kit game this year. Still working on the supply line to make it all viable. Hopefully the first prototype will fly sometime next week.
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calgoddard
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« Reply #21 on: September 05, 2018, 12:03:45 PM »

Maxout -

Bravo!  I am sure your WS kit will be a good one.
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Maxout
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« Reply #22 on: September 06, 2018, 08:53:59 AM »

Maxout -

Bravo!  I am sure your WS kit will be a good one.

Don't get too excited. This is uncharted territory for me. It's probably going to be a very conventional kit for this go-round.
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« Reply #23 on: September 07, 2018, 09:31:13 AM »

Maxout-

I looked at your videos.  They are very informative and instructive, thank you.  I have seen the Wards' planes are given poor reviews and many of the other kits/supplies are also over priced and trashed by many who get them.  It looks like Wards is part of VWR scientific, a very large company selling research supplies/equipment.  You are better off looking around on Amazon or other niche Mom and Pop stores selling similar items of better quality and larger variety.

One suggestion is to share some safety tips in launching these planes.  My son held his plane in a bit too close and the wing clipped his temple.  We will have him (and his partner) wear safety goggles moving forward. This is also specified in the SO rules.  So far we have not had a plane loop and hit us in the head. Grin

Regards,
Lee
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Little-Acorn
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« Reply #24 on: September 07, 2018, 07:09:34 PM »

With the stock Ikara (24cm) flaring prop, we were testing at around 0.075g/in rubber, which is larger than 3/32 (cut from 1/8" stock last year for heli class). We did not see any stability issues nor rolling in, granted the wing is slightly longer (40cm) than this year's rules. We'll probably try up to about 12" initially.

But, the pusher is definitely and interesting option.

Chuck


I got a 1 min 55 sec flight on the canard pusher in the gym yesterday with a 6" (15cm) Ikara prop and a 0.72" thick motor, a 28" loop, unlubricated. I put 3,000 winds into it, which is probably not the max for a 28" loop, I'm just starting to trim it for good flights and have a long way to go, I'm sure. It bonked the ceiling twice, obviously needs a thinner motor, I will try .067" and .062" next. A well-known kit producer remarked to me that with the tandem tractor designs he's putting together for 2019, 3-minute flights are definitely in the cards.

Before that, I tried it with an .083" motor and a homemade 7-1/2" prop, made with a hub from a 6" Ikara and cut-down blades from Freedom Flight Models. 1 min 40 sec was the best I got from it before switching to the smaller prop and motor.

In both cases I turned the prop around on its axle to make a pusher prop out of it. As noted before, winding it up backward was odd.

Most impressive thing about this canard pusher, is that it doesn't have any of the bad habits my tractors do. None of this propeller-fin-effect jazz, stabs that lift downward etc. Both horizontal surfaces lift upward. And the looong motor stick HELPS the balance, doesn't hinder it.

Total weight without rubber is 8.21 grams. I have a small, sawed-off 5D nail rubberbanded to the front, in front of the stab, about 0.5 grams. I might soon try a 36" long motor stick (light 3/16 x 3/8 balsa), just because. Weird-looking plane, by hey, it flies. Fairly well, even. I slapped it together with square corners and little grace, trying for adjustability, not beauty (obviously). Still haven't figured out how I warped the front stab, it has a slight airfoil shape like the wing.

Next version will have a swept-back rear wing (around 20 degrees sweep in each panel) with the vertical fins on the tips, and probably a swept-back leading edge on the front stab, set back about an inch and a half from the front tip of the motor stick, just so it won't break WHEN I hit a wall. And so it looks a little more cool.

Theoretically a larger, slower-turning prop should be more efficient than a smaller, faster-turning one. But the 6" Ikara seems very efficient, and maybe my propeller-fu just isn't in good harmony with the universe. I've just started testing, and no doubt have a long way to go before I come anywhere near its max potential. See attached pics.
Attached files Thumbnail(s):
Re: Any word on Div. C Wright Stuff planes for 2018-2019 season?
Re: Any word on Div. C Wright Stuff planes for 2018-2019 season?
Re: Any word on Div. C Wright Stuff planes for 2018-2019 season?
« Last Edit: September 07, 2018, 07:24:53 PM by Little-Acorn » Logged
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