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Author Topic: P-30 with CF  (Read 2484 times)
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tgwhitley
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« on: March 11, 2013, 10:49:55 PM »

Is there a good P-30 design with carbon fiber used to stiffen/strengthen wing? Hope to learn something and help with Coupe builds later

Thanks

Tim

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DerekMc
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« Reply #1 on: March 11, 2013, 10:56:00 PM »

I don't know of a design that has it on the plan. I would think one can use carbon rib caps and trailing edges without to much trouble on pretty much any modern P30.
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« Reply #2 on: March 11, 2013, 11:33:32 PM »

Hi Tim.

I have been looking at a lot of p30 designs in the FFQuartly P30 special issue recently and didn't see any usage of CF.

the p30 minimum *airframe* flying weight is 40 grams and that in and of itself is difficult to attain do just using balsa, tissue, and perhaps a round/hollow CF wing spar. The extra cf strips and glue weight could add up quickly on a p30.

The coupe has a 70gm minimum weight and it is much easier to use the CF with the extra 30gm difference.

Check out the FFQuarterly Coupe special issue http://freeflightquarterly.com/wordpress/?page_id=5 to see if there is more Cf info to get you there sooner.

 take care, js
http://freeflightquarterly.com/wordpress/wp-content/uploads/2010/08/Coupes-Survey-2009-cover-212x300.jpg



P-30 with CF
« Last Edit: March 12, 2013, 12:24:39 AM by jswain » Logged
applehoney
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« Reply #3 on: March 12, 2013, 01:06:50 AM »

40g isn't difficult to attain with balsa and tissue -  and no need for CF at all to provide stiff wing structures
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DerekMc
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« Reply #4 on: March 12, 2013, 01:56:52 AM »

Jim you are right. There is no need for carbon on a P30. But they would make a simple practice bed to learn carbon building techniques. And if one did manage to make one to weight then ones Coupe would certainly be to weight!
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Tapio Linkosalo
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« Reply #5 on: March 12, 2013, 03:19:42 AM »

I designed this simple model (since kitted by a finnish cottage company) some 20 years ago; the kit had all balsa wing construction. More recently I modified the wing structure for carbon tube spar (5mm roots and 3.5mm tips) and carbon trailing edge (the backs of the ribs are reinforced with short cap strips to hold the trailing edge in place). The new wing is much stronger, both for flight and handling loads, and also stiffer against torsional loads. So I definately claim that this kind of structure is superior compated to balsa one. And not at all more complicated to build, the carbon trailing edge saves the selection and planing the spar to a triangle...
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Re: P-30 with CF
Re: P-30 with CF
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dephela
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« Reply #6 on: March 12, 2013, 08:38:58 AM »

Art Ellis held the record using a lot of carbon in his "Windowplane", plans were in the NFFS Sympo around 1999.
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Dennis
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« Reply #7 on: March 12, 2013, 10:05:16 AM »

Nice design, Tapio.

While I agree that CF can make a structure stiffer I question why it's necessary to go to an overkill situation for P30.

Such structures come into their own as aspect ratios and flight stresses increase - not a problem where maximum span is limited to 30".  Within the parameters of P30 rules a stock balsa/tissue assembly can be more than adequate for handling, flight and torsional loads.   I was once jokingly chided for my 'meteoric launches' but I've never folded a wing yet and structures are stable.

Use of CF often requires the use of CA or epoxy.  I am totally allergic to the former - nasty stuff that I only use on the field whilst standing upwind of it - ad slightly skin allergic to the latter so I use that with discretion o the few occasions I find a need.  I do appreciate that, therefore, my views on such are biased.

Trailing edges? Strip selection and carving is, for me, just a part of building, not a chore.
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RalphS
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« Reply #8 on: March 12, 2013, 10:29:38 AM »

I am a fan of CF in wings and tail planes.  Here are a couple of pics of my P30 No 4.  CF is used to stiffen the balsa LE, to cap spar and ribs and for the TE.
Decent model on 4 strands of 1/8".  Has won a couple or so of comps in it's time.  The nice thing about using CF in the surfaces is that the models keep their trim.  The downside is that they take longer to build.
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Re: P-30 with CF
Re: P-30 with CF
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NormF
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« Reply #9 on: March 12, 2013, 10:48:09 AM »

i believe some , if not all, the Starlink P-30's feature carbon tube spars. The tubes are also available from Starlink. See: http://starlink-flitetech.com/P30.php

- Norm
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Tmat
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« Reply #10 on: March 12, 2013, 11:24:11 AM »

I don't do tissue. Ever. So without the torsional rigidity that the tissue provides a standard balsa structure seems a bit too floppy to me with mylar covering (which I prefer for light models like P-30s or Coupes). So I like to use carbon fiber cap strips and trailing edges and tubular spars to keep the structure stiff, and straight.
But certainly a simple, traditional balsa structure with tissue covering is adequate for P-30. But I don't do tissue. So carbon gets a work out in my workshop. It's not hard to work with (imo) and I like the stability that it provides.
But certainly different strokes for different folks and all that....

Tmat
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danberry
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« Reply #11 on: March 12, 2013, 01:51:24 PM »

PoleCat uses cf caps on the ribs.
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duration
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« Reply #12 on: March 12, 2013, 03:30:47 PM »

Mike Evatt's mostly carbon fiber P-30 is featured in the 2003 NFFS Symposium. It uses a very narrow carbon fiber D-box, CF trailing edge, and carbon-capped Rohacell ribs. There are several variations of the design, including a tandem pusher, and two sizes of geared models. The article is repeated in the FFQ P-30 Survey, beginning on page 77.

Phil Ball's geared P-30 is in the Free Flight Forum 2010. The wing uses a ready-made carbon fiber F1A tail leading edge as the D-box, carbon trailing edge, and carbon-capped balsa ribs. Weight is given as 11g. The F1A tail leading edge is from Szabo, cat. no. 170. (I believe the e-mail contact for Szabo on Hip pocket somewhere.) Like the Evatt models, the very narrow D-box (3/8 - 1/2") carries all the bending and torsion loads; there are only ribs connecting leading edge to trailing edge.

Both Evatt's and Ball's wings might seem minimal to those used to traditional stick and tissue structures, but carbon fiber is amazing stuff---a little bit goes a long way. As Tony pointed out, a carbon fiber structure is not dependent on the covering for strength, so you don't have to worry about damp tissue, etc. More importantly, you can use 1/4 mil mylar, which is much lighter then tissue. So the weight ends up about the same, but the wing is much stiffer.

An alternative to a carbon D-box that might be worth considering is to build a full-depth 1/16 balsa spar, cap top and bottom with CF; use carbon-capped diagonal ribs in front of the spar with a light balsa leading edge and straight carbon-capped ribs aft of the spar with a cf trailing edge. The capped diagonal ribs work much like a D-box to provide torsional strength. There is no need for diagonal ribs aft of the spar. If you go to page 98 in the P-30 survey, look at F1g. 6, example D4.

As Jim Bradley once said: "As my models get blacker, they get stronger"

Louis

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tgwhitley
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« Reply #13 on: March 12, 2013, 06:14:44 PM »

I have the FFQ P-30 survey book in transit. I am looking forward to reading from cover to cover. I would like to obtain copy of Polecat plans can someone point me in correct direction a pdf would be great.

Thanks

Tim
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Dave Andreski
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« Reply #14 on: March 12, 2013, 08:09:35 PM »

I would like to obtain copy of Polecat plans can someone point me in correct direction a pdf would be great.

Thanks

Tim

Don DeLoach designed the "Polecat", now "Polecat X" and is an inactive member here. His user name is dadl72. Go to his 'user profile' and note that you can e-mail him. I'm sure he'd be more than happy to sell you a plan sheet. He may still be selling sets of laser cut ribs to help get you started.

Dave
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tgwhitley
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« Reply #15 on: March 13, 2013, 09:13:24 AM »

Dave

Thanks for the information have ribs and plan for polecat on the way from Don. Thanks for all the responses this board is very useful in the wisdom sharing ability and helpful attitude toward new members.

Tim
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Dave Andreski
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« Reply #16 on: March 13, 2013, 09:26:44 AM »

Wow,
That was fast Tim!
Good goin'.
I never got around to building mine Undecided
Dave
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« Reply #17 on: March 13, 2013, 11:24:17 AM »

I'm going to "stir the pot" here a little...

Do you think that the subject of this thread and the responses go against the spirit of P-30?

Or, is P-30 just another one of those events that have evolved from what was once intended to be a "beginners" event to just another expert event?
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« Reply #18 on: March 13, 2013, 11:48:50 AM »


Do you think that the subject of this thread and the responses go against the spirit of P-30?

Or, is P-30 just another one of those events that have evolved from what was once intended to be a "beginners" event to just another expert event?

No, use of CF doesn't = expert. In fact it's easier to build a strong warp free airplane with judicious use of CF. The techniques aren't more difficult but you won't run into them in traditional stick and tissue. That doesn't mean that stick and tissue is "easier". With CF the quality of the balsa isn't as important. That's one thing traditional Modelers tend to forget. They know quality balsa by feel, touch and sense. That takes time to develop.



And yes you will find very good flyers with P30's, the reason being is that they are fun to fly and inexpensive. I fly P30 and have fun. I try to share my knowledge with anybody else who is flying if they are open to it. Building "full house" P30's doesn't interest me but I think there cool.

I am interested in geared P30 because I would like to use coupe motors. With all the gears available now for model helicopters it shouldn't be to hard to come up with a nice set up.
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tgwhitley
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« Reply #19 on: March 13, 2013, 01:27:59 PM »

My original question or thought was can I learn using cf on P-30 for later Coupe builds. No intention of making P-30 more complex than necessary for other modelers. I am cutting parts now for a Dragonfly by Dave Platt from 1988 Model Aviation it has 1/16 CF rods for wing saddle. Can a traditional rolled tube or stick and tissue model compete and be fun very much so in my extreme low experience opinion.

Tim

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DerekMc
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« Reply #20 on: March 13, 2013, 02:00:26 PM »

O don't worry Tim. Anytime P30 comes up one can expect the conversation to evolve the way it has on this thread Cheesy As I said earlier a P30 is a nice test bed for new construction techniques so go for it!
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Derek
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« Reply #21 on: March 13, 2013, 04:01:38 PM »

My original question or thought was can I learn using cf on P-30 for later Coupe builds. No intention of making P-30 more complex than necessary for other modelers. I am cutting parts now for a Dragonfly by Dave Platt from 1988 Model Aviation it has 1/16 CF rods for wing saddle. Can a traditional rolled tube or stick and tissue model compete and be fun very much so in my extreme low experience opinion.

Tim



Hi Tim,
I must commend you on your choice of design. To me the "Dragonfly" is the most classic/elegent design P-30's that's ever been put on paper. A beautiful model that captures that look of "Yesteryear" perfectly. I guess you can tell I like models with more curved and rounded design features. Much more pleasing to the eye.(think of a beautiful womens features here) You can be as competitive in P-30 as you choose to be. Carbon Fiber isn't going to determine your abilities or level of fun,"YOU ARE". Flying "F1G" (Coupe) in competition is a whole other game. Too be competitive in "F1G" you will need a much more complicated model.
Thom 
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Dave Andreski
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« Reply #22 on: March 13, 2013, 04:27:08 PM »

I'm going to "stir the pot" here a little...

Do you think that the subject of this thread and the responses go against the spirit of P-30?

Or, is P-30 just another one of those events that have evolved from what was once intended to be a "beginners" event to just another expert event?
Expert, to me, means more about the skill of the flyer regardless of how an aircraft is constructed.
If you want to become an expert you must fly, fly, then fly some more!
Dave
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« Reply #23 on: March 13, 2013, 07:54:22 PM »

PICKING AIR - THE GREAT EQUALIZER !!  Wink
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jswain
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« Reply #24 on: March 13, 2013, 09:37:55 PM »

...I am cutting parts now for a Dragonfly by Dave Platt from 1988 Model Aviation...
Tim

very nice looking model, best wishes and have fun.

btw, when i received my p30 SparrowHawk plans they inculded a photo copy of the original AMA magazine article which was really nice.

js
http://www.modelaircraft.org/plans/images/1988/585.jpg
P-30 with CF
« Last Edit: March 13, 2013, 11:34:00 PM by jswain » Logged
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