Logo
Builders' Plan Gallery  |  Hip Pocket Web Site  |  Contact Forum Admin  |  Contact Global Moderator
February 19, 2020, 07:39:21 PM *
Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with email, password and session length
 
Home Help Search Login Register
Pages: 1 [2] 3 4 5 6 7 8 9 ... 30   Go Down
Print
Author Topic: CATAJETS: Design and Development  (Read 65710 times)
0 Members and 1 Guest are viewing this topic.
Pit
Palladium Member
********

Kudos: 129
Offline Offline

Germany Germany

Posts: 5,507


Topic starter
aka staubkorb


WWW

Ignore
« Reply #25 on: July 06, 2010, 04:49:58 PM »

It's truly surprising what a tiny bit of imbalance will do to these smaller planes (I SHOULD know better - or lay off the beer Roll Eyes).  The right panel was 0.13 grams heavier Lips sealed.

Laterally balanced, all added warps/tabs removed - except for the gurney strip on the bottom TE of the stab - and the puppy sails clear across the backyard 10 for 10. Before, it was not consistent getting maybe 50% glides that looked ok. Now, they don't look ok, they are GOOD (and fast). It appears that the Scorpion needs very little to NO neg. incidence on the tailplane (<0.5°) - the Phillips entry on the wing might be enough, possibly because the high stab location is above the wing downwash(?).

Hoping for calm tomorrow morning or afternoon. An evening outing is out of the question with the semi-final against Spain. Too bad the Netherlands squeaked by Uruguay (sorry, Wout).
Logged

A Dedicated Convert to:
WWWoFF (Wonderfull Wacky World of Free Flight)

Comparing Spammers to a pile of organic waste is an insult to the organic waste!
chunkymonk
Bronze Member
***

Kudos: 0
Offline Offline

United Kingdom United Kingdom

Posts: 13



Ignore
« Reply #26 on: July 09, 2010, 05:30:44 AM »

Just a couple of quick photos showing my last 2 Models. The latest being a model of Burt Rutans Space Ship 1. Modified from the Ebenezer Plan by John Kay and scaled down to a span of 6"! Built in an hour sat around after work and test flights (by hand) went well last night. Plan will come soon.
Attached files Thumbnail(s):
Re: CATAJETS: Design and Development
Re: CATAJETS: Design and Development
Logged
lemuel
Platinum Member
******

Kudos: 59
Offline Offline

Australia Australia

Posts: 1,813


A peanut a day keeps the doctor at bay..

WWW

Ignore
« Reply #27 on: July 09, 2010, 05:42:47 AM »

Great designs Chunky! well done.

regards
matthew
Logged

two wings = GOOD, no wings = BAD Sad
Pit
Palladium Member
********

Kudos: 129
Offline Offline

Germany Germany

Posts: 5,507


Topic starter
aka staubkorb


WWW

Ignore
« Reply #28 on: July 09, 2010, 09:22:30 AM »

Right on, chunkymonk! That's what it's all about! The Vamp looks like it has some flight rash(?).
Logged

A Dedicated Convert to:
WWWoFF (Wonderfull Wacky World of Free Flight)

Comparing Spammers to a pile of organic waste is an insult to the organic waste!
Willi_S.
Bronze Member
***

Kudos: 0
Offline Offline

Germany Germany

Posts: 12



Ignore
« Reply #29 on: July 10, 2010, 12:33:55 PM »

Hello.

I have just cut out all the pieces for Bernard's MiG 15. Soon I will glue it together.

But one thing is not in BGs drawing: where should be the CG?

regards

Willi
Logged
Sky9pilot
Titanium Member
*******

Kudos: 50
Offline Offline

United States United States

Posts: 2,734


WWW

Ignore
« Reply #30 on: July 10, 2010, 06:33:31 PM »

Chunky,

Great looking models...love the Spaceship 1 and the Vamp. How do you hold them for launch?

Tom
Logged

Best Regards,
Sky9pilot
    "If God is your Co-pilot, consider switching seats!" 
http://www.stickandtissue.com/cgi-bin/yabb2/YaBB.pl
http://freeflightarchive.com/index.php/homepage-2
Pit
Palladium Member
********

Kudos: 129
Offline Offline

Germany Germany

Posts: 5,507


Topic starter
aka staubkorb


WWW

Ignore
« Reply #31 on: July 10, 2010, 07:30:11 PM »

After getting the F-89 flying very nicely today, I "had" to get that "one more flight" Undecided

 It'll get fixed, with a smidge more dihedral. Gory details in the "went flying " thread.
Attached files Thumbnail(s):
Re: CATAJETS: Design and Development
Re: CATAJETS: Design and Development
Logged

A Dedicated Convert to:
WWWoFF (Wonderfull Wacky World of Free Flight)

Comparing Spammers to a pile of organic waste is an insult to the organic waste!
lemuel
Platinum Member
******

Kudos: 59
Offline Offline

Australia Australia

Posts: 1,813


A peanut a day keeps the doctor at bay..

WWW

Ignore
« Reply #32 on: July 10, 2010, 08:46:25 PM »

Those catapult launch models are dangerous. They are usually the ones that you fly the most when you get to the field....

regards
Matthew
Logged

two wings = GOOD, no wings = BAD Sad
Pit
Palladium Member
********

Kudos: 129
Offline Offline

Germany Germany

Posts: 5,507


Topic starter
aka staubkorb


WWW

Ignore
« Reply #33 on: July 10, 2010, 09:13:56 PM »

 Grin

The Born Loser and P. Flash only got 1 flight each. The rest was all catafull, culminating with the 5 minute + flight of the new Kitty Katze. The Cougar got the most out of the nice HOT weather.
Logged

A Dedicated Convert to:
WWWoFF (Wonderfull Wacky World of Free Flight)

Comparing Spammers to a pile of organic waste is an insult to the organic waste!
Willi_S.
Bronze Member
***

Kudos: 0
Offline Offline

Germany Germany

Posts: 12



Ignore
« Reply #34 on: July 13, 2010, 02:25:42 AM »

Hello.

I finished my first catajet now - the MiG 15 according to BGs plan. It came out a bit heavy at 13.7 g flying weight.

On ask for giving me information about the C of G a few posts further up I didn't get any reply. So I found 'my' C of G by trial and error until the jet made a nice glide from a throw out of my hand with a slight tendency turning to the left. Then on to the first catapult launches. The model makes a nice corkscrew up with about 1 1/2 turns to the left. Then it rolls or loops into level flight. But then it behaves very strange! In 1 of 5 launches it gets into a nice left hand glide with a bit of wingdropping to the left. But every 'drop' is recovered and it glides on.

In 4 of 5 launches it rolls into level flight. Then the forward motion nearly stops and the model turns left into a very stable spin to the ground. No recovery from this spin at all. This happened very consistently in a row until 1 'normal' glide occurs. The next launches again ended in a spin. The spin is not fast but very stable.

I tried many rudder- and elevator trim settings but nothing really worked! Is anybody out there who can give me some advice what to do.

I'm an absolute newby to catapult launched gliders. I can make a control line stunt ship fly and I can set the trim for a F1A glider or an indoor rubber job but catajets are a mystery to me.

Kind regards

Willi
Attached files Thumbnail(s):
Re: CATAJETS: Design and Development
Re: CATAJETS: Design and Development
Logged
Pit
Palladium Member
********

Kudos: 129
Offline Offline

Germany Germany

Posts: 5,507


Topic starter
aka staubkorb


WWW

Ignore
« Reply #35 on: July 13, 2010, 08:30:08 AM »

Hello Willi,

That is EXACTLY the same "problem" that I have (had) with the F9F Cougar. I have apparently solved the problem by adding (a scale feature) boundary layer fences (stall strips) to the wing about one third panel span on each side - the full-size MiG has them also. I just put them on the top surface (1/16th sq strips about one inch long), but it is probably better on top AND bottom. The plane now glides consistently.

Swept wing aircraft like to fly fast and LAND fast. Grumman found this out with the Cougar and added the fences to cure the slow speed handling problems - it also works for models. The fences "keep" the air on the wing. You might also add a very small amount of noseweight and a fair amount of washout to both wings.

Will you be coming to Lampertheim this Fall?
Logged

A Dedicated Convert to:
WWWoFF (Wonderfull Wacky World of Free Flight)

Comparing Spammers to a pile of organic waste is an insult to the organic waste!
Willi_S.
Bronze Member
***

Kudos: 0
Offline Offline

Germany Germany

Posts: 12



Ignore
« Reply #36 on: July 13, 2010, 10:03:39 AM »

Hi Pete.

Thank you for your advice! I will try the wing fences immediately.

The outer wings had a fair amount of washout from sanding the wing profile. And I 'tweaked' in even more during the flying session.

I hope I will be in Lampertheim this fall. What about you and the Interscale in November in Nijmegen/Netherlands?

Kind regards

Willi
Logged
Pit
Palladium Member
********

Kudos: 129
Offline Offline

Germany Germany

Posts: 5,507


Topic starter
aka staubkorb


WWW

Ignore
« Reply #37 on: July 13, 2010, 10:30:57 AM »

I'm hoping to make the Interscale meet, but with the luck I've had this year with trying to "plan" anything... I might even have something to fly (never flown indoors).
Logged

A Dedicated Convert to:
WWWoFF (Wonderfull Wacky World of Free Flight)

Comparing Spammers to a pile of organic waste is an insult to the organic waste!
JetPlaneFlyer
Gold Member
*****

Kudos: 37
Offline Offline

United Kingdom United Kingdom

Posts: 490



Ignore
« Reply #38 on: July 13, 2010, 10:41:20 AM »

The flat spin on swept wing models often means you need to move the CG forward and add more negative on the stabiliser.. But this would make a catapult model 'loopy' so might be no use.

Washout and wing fences are also very good ideas. The problem is that on swept wings the tips tend to stall first and because the tips are behind the CG when the lift from a tip is lost the nose pitches up and the model rotates toward to stalled wing producing the familiar flat spin.

Steve
Logged
Sky9pilot
Titanium Member
*******

Kudos: 50
Offline Offline

United States United States

Posts: 2,734


WWW

Ignore
« Reply #39 on: July 14, 2010, 01:16:01 AM »

Willi... the Mig looks great.

JetPlaneFlyer and Pete... thanks for all the input and advice... still working on the Me163A. have cut the elevons out and added wire tie hinges so they are fully adjustable. Will begin adding weight to the nose to see if we can get her flying... thanks again for the advice... as Matt said, hard to fly the other planes when the catajets are around... they truly are addictive.

Thanks again guys,
Tom
Attached files Thumbnail(s):
Re: CATAJETS: Design and Development
Logged

Best Regards,
Sky9pilot
    "If God is your Co-pilot, consider switching seats!" 
http://www.stickandtissue.com/cgi-bin/yabb2/YaBB.pl
http://freeflightarchive.com/index.php/homepage-2
Willi_S.
Bronze Member
***

Kudos: 0
Offline Offline

Germany Germany

Posts: 12



Ignore
« Reply #40 on: July 14, 2010, 03:08:48 AM »

Hello.

I added wing fences to the MiG and did some more trying yesterday in the evening. The MiG now behaves much better in the glide, but the problem with the stallspin is not entirely cured! In 1 launch of about 10 it occurs again.
The greatest step forward brought a change in my launch routine. At first I launched nearly 45° upward and with a slight angle of the model to the right with all the power my rubber band would deliver. I changed my technique to launching nearly horizontally and the model banks about 80° to the right. Only 75% of the possible power of the rubber is given to the model.
Bingo! This works fantastic. After launch the MiG now proceeds a huge half loop and rolls to the left. This gives a very smooth transition and a nice fast glide with a wide lefthand curve. The times were consistently 15 to 16 seconds and few very good flights with 20 seconds or a bit more. The hights I reached I would estimate as 15 to 18 m. The flight times Pete or BG mentioned of 35 sec. or more were not possible for me.

If I altered the slightest bit in this procedure then there was a bad transition (even the above mentioned stallspin occurred) or the heights were bad or other not so nice things happened.

I have cut the parts for the next catajet in the hope that it becomes lighter and the flight times would be longer. It is based on the numbers of BG's MiG 15 but I changed the outline to look more like a mixture of the French Mystere fighter jet and a Sabre. When it is finished I will post a picture or two.

I have to agree with Matthew - those catapult launched models are dangerous! You can't stop launching and chasing!

Kind regards

Willi
Logged
Sky9pilot
Titanium Member
*******

Kudos: 50
Offline Offline

United States United States

Posts: 2,734


WWW

Ignore
« Reply #41 on: July 20, 2010, 02:54:40 AM »

Hello All,

Here's my latest project... the Douglas Skystreak D-558-1

Had a few hours free this afternoon and was able to cut out parts and sand the wing. I tried to sand a taper from root to tip from 3/32 to 1/32 then sand in an airfoil at the 25% point from the leading edge of the wing. Horizontal tail surface is 1/32 balsa. The fuselage is a sandwich of two outside fuselage shapes from 1/32 and a center core of 1/16 balsa with the grain vertical glued in four sections of approximately 3 inch sections and the fourth section includes the Vertical Stab and Rudder, not included on the outside forms. I gave the wing a 15mm dihedral with one panel lying flat on the building board and the opposite tip raised. The Wing was one solid piece that was scored in the center and cracked up to the 15mm and pinned and braced at the dihedral and then glued with thick cyano.

I haven't done any glide attempts with it yet will try tomorrow in the morning... will experiment with incidence starting with approximately 1 degree negative incidence on the horizontal stab.

I've decided to use the early NACA experimental white scheme, once the gliding trials are accomplished. It this is successful I post the plans for it with any corrections. Just got the rough drawing on 8.5 X 14 inch paper (Legal Size in USA)

Here's some pics.

Tom
Attached files Thumbnail(s):
Re: CATAJETS: Design and Development
Re: CATAJETS: Design and Development
Re: CATAJETS: Design and Development
Re: CATAJETS: Design and Development
Logged

Best Regards,
Sky9pilot
    "If God is your Co-pilot, consider switching seats!" 
http://www.stickandtissue.com/cgi-bin/yabb2/YaBB.pl
http://freeflightarchive.com/index.php/homepage-2
Sky9pilot
Titanium Member
*******

Kudos: 50
Offline Offline

United States United States

Posts: 2,734


WWW

Ignore
« Reply #42 on: July 21, 2010, 06:02:20 PM »

Hi All,

Trying to catch up on all the promised builds...Here's my mockup of the Natter at 8 inch span. Fuselage is amazingly large for this bird. I've tried to employ all the points that have been made in the various threads... Pete's sanding of the main wing tapering to the tips from the 3/32 root to 1/32 or a little thinner at the tips with the airfoil then sanded to a trailing edge 1/64 or there abouts. sanding the fuselage to a taper at the tail.

Hopefully I'll see some fair times with these latest models...

Pete your Reichenberg is next. Thanks to all for all these great models and the fun they bring.... now to the finishes/schemes

Regards,
Tom
Attached files Thumbnail(s):
Re: CATAJETS: Design and Development
Re: CATAJETS: Design and Development
Re: CATAJETS: Design and Development
Logged

Best Regards,
Sky9pilot
    "If God is your Co-pilot, consider switching seats!" 
http://www.stickandtissue.com/cgi-bin/yabb2/YaBB.pl
http://freeflightarchive.com/index.php/homepage-2
lemuel
Platinum Member
******

Kudos: 59
Offline Offline

Australia Australia

Posts: 1,813


A peanut a day keeps the doctor at bay..

WWW

Ignore
« Reply #43 on: July 21, 2010, 06:20:40 PM »

Nice work on the natter! I have given mine away to my nephew and hope he gets some fun with it. The natter does fly but you need a really good day of thermal activity to get some extra lift. Good luck.

regards
matthew
Logged

two wings = GOOD, no wings = BAD Sad
Sky9pilot
Titanium Member
*******

Kudos: 50
Offline Offline

United States United States

Posts: 2,734


WWW

Ignore
« Reply #44 on: July 23, 2010, 05:19:48 PM »

Hi All,

I have done some more work with the Natter... Some glides in the front yard resulted in changing the incidence of the horizontal stab, adjusting the weight ballast on the nose. Once the proper amount of ballast is accomplished I'll take the clay off and weigh it and add some lead to the nose in drilled holes which will be covered later. It takes a pretty hard toss to get the little wings flying in this bird.

Here's the pics of the semi finished camo of black under surfaces and mottled grey topside. I used acrylic artist paints and drybrushed the mottled spots on the grey. I used two sizes of black sharpie pens and a white jell pen for the panel lines on the black surfaces.

Regards,
Tom
Attached files Thumbnail(s):
Re: CATAJETS: Design and Development
Re: CATAJETS: Design and Development
Re: CATAJETS: Design and Development
Re: CATAJETS: Design and Development
Logged

Best Regards,
Sky9pilot
    "If God is your Co-pilot, consider switching seats!" 
http://www.stickandtissue.com/cgi-bin/yabb2/YaBB.pl
http://freeflightarchive.com/index.php/homepage-2
lemuel
Platinum Member
******

Kudos: 59
Offline Offline

Australia Australia

Posts: 1,813


A peanut a day keeps the doctor at bay..

WWW

Ignore
« Reply #45 on: July 23, 2010, 05:50:48 PM »

Yes, she ain't no floater. It would thermal though I believe. Nice Job! you are an excellent painter/ finisher.

regards
Matthew
Logged

two wings = GOOD, no wings = BAD Sad
Sky9pilot
Titanium Member
*******

Kudos: 50
Offline Offline

United States United States

Posts: 2,734


WWW

Ignore
« Reply #46 on: July 23, 2010, 06:44:20 PM »

Matthew,

Thanks for the comments ... I'm looking forward to putting her on the catapult as soon as I finish the front lawn trimming. Should be fun with the fetchermites Grin Cheesy Smiley

Regards,
Tom
Logged

Best Regards,
Sky9pilot
    "If God is your Co-pilot, consider switching seats!" 
http://www.stickandtissue.com/cgi-bin/yabb2/YaBB.pl
http://freeflightarchive.com/index.php/homepage-2
Sky9pilot
Titanium Member
*******

Kudos: 50
Offline Offline

United States United States

Posts: 2,734


WWW

Ignore
« Reply #47 on: July 24, 2010, 03:03:02 AM »

Hi All,

Got the Bachem Ba 349 Natter trimmed after adding approximately a negative 2 degrees of incidence on the horizontal stab and removing some ballast and with a hefty toss got her to fly across the lawn and into the neighbor's yard ...15 to 20 yards. I was pleased to say the least to see her glide like that. May do pretty well off the catapult.

While I was at it I got the Douglas D-558-1 Skystreak trimmed and she was suprising... with a negative 1 degree of incidence and a little less ballast on the nose she took off in a very flat glide and crossed the lawn the neighbors driveway and out into the street, broke off the toothpick hook but was really sweet to see.

The model was finished with Artist Acrylic paints thinned with water. Markings were made with photoshop and printed on thin mailing labels cut to size. The panel lines were fine Sharpie permanent marker. I borrowed Chris Starleaf's suggestion of using a straight edge cut from thin cardboard (cereal box) so that it can be bent over the fuselage.

Here's the finished Skystreak pics...Can't wait to get her on the cat. I think with the sanding of the wing as Pete suggested and tapering the fuselage even at the finished weight of 18.9 grams with ballast she'll fly...again I don't compete so just some local park flying will be quite satisfying. I find the painting pretty good therapy. If she flies fairly well...I'll post the plans on site.

Regards,
Tom
Attached files Thumbnail(s):
Re: CATAJETS: Design and Development
Re: CATAJETS: Design and Development
Re: CATAJETS: Design and Development
Re: CATAJETS: Design and Development
Logged

Best Regards,
Sky9pilot
    "If God is your Co-pilot, consider switching seats!" 
http://www.stickandtissue.com/cgi-bin/yabb2/YaBB.pl
http://freeflightarchive.com/index.php/homepage-2
lemuel
Platinum Member
******

Kudos: 59
Offline Offline

Australia Australia

Posts: 1,813


A peanut a day keeps the doctor at bay..

WWW

Ignore
« Reply #48 on: July 24, 2010, 07:57:29 PM »

Looks very cool!
Logged

two wings = GOOD, no wings = BAD Sad
Sky9pilot
Titanium Member
*******

Kudos: 50
Offline Offline

United States United States

Posts: 2,734


WWW

Ignore
« Reply #49 on: July 26, 2010, 08:05:11 PM »

Thanks Matt,

I got out for some flying today and was very pleased with both models.... the Ba349 Natter has great potential... got a good flight after a little tweaking of the ballast and the launch technique. She didn't like the full stretch of the cat rubber... would only do a huge loop. After backing off on the stretch a bit and angling the launch slightly off directly into the wind and a slight bank (I launch left handed) on the cat she climbed in a nice left hand spiral and then rolled out on top into a right circle with a very nice flat glide. I tried to time her with my sweep hand on my watch and got approximately 19 seconds. Was very pleased with this. I feel certain that I can break my 20 second barrier at the local park.  Unfortunately my Fetchermite tripped on the retrieval and broke the main wing off the fuselage... After repair and time to dry with cyano I repeated a flight of 18 seconds.  Grin Roll Eyes

The Skystreak D-558-1 still needs tweaking...I was only able to get a large loop...need incidence reduced on the horizontal stab. The glide was fairly flat with a little stall quickly recovered from. I thing the incidence correction of about 1/2 degree should cure this. Other wise I think she should start flying very well. I forgot the camera so no flight shots as of yet.

Thanks to Pete and the guys who have shared the building and trimming techniques on this and the related threads... I've learned a lot and have really enjoyed the flying and the Fetchermites have had a lot of fun as well.

I'm going to refine the Douglas Skystreak D-558-1 plans a bit more before uploading them to the plans site.

Regards,
Tom
Logged

Best Regards,
Sky9pilot
    "If God is your Co-pilot, consider switching seats!" 
http://www.stickandtissue.com/cgi-bin/yabb2/YaBB.pl
http://freeflightarchive.com/index.php/homepage-2
Pages: 1 [2] 3 4 5 6 7 8 9 ... 30   Go Up
Print
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.21 | SMF © 2015, Simple Machines Valid XHTML 1.0! Valid CSS!