SFA Forum - Frustrating Jet Catapult gliders

JoshuaF

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Re: Frustrating Jet Catapult gliders
Reply #195 - Jun 16^th, 2009 at 12:21pm

Dan, I personally use the AMA catapult as well, but have tried the Canberra on a much larger one, with very impressive results. Expected it to go nuts, but it just seems happier the more power you give it. It has too much incidence for either, though, and ends up slightly nose down before transitioning, but the point is that it works.

As for being optimal, I don't know about that. There are a couple designs out there that might be significantly better. If you can tame it, the Meteor is definitely one of them. Some of the early Ilyushin jets are good, too, as well as the AR 234.

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edgemitchell Offline Get small Posts: 711 Washington, DC	Re: Frustrating Jet Catapult gliders Reply #196 - Jun 25^th, 2009 at 7:55am Hi all....I have a P80 Jet Cat on the boards. I'll be trying it out next time I have a chance...14" ws.
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edgemitchell Offline Get small Posts: 711 Washington, DC	Re: Frustrating Jet Catapult gliders Reply #197 - Jun 25^th, 2009 at 7:57am I thought catapult size was limited?
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JoshuaF

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Re: Frustrating Jet Catapult gliders
Reply #198 - Jun 25^th, 2009 at 8:36am

edgemitchell wrote on Jun 25^th, 2009 at 7:57am:

I thought catapult size was limited?

I just checked the rule book again, and my reading is that a 2 meter high start launched model would meet the rules. Sure, you'd get thrown off the field for that, but the rules don't say anything against it, not even that the catapult must be hand held.

Nice looking P-80. Hope it works out well for you.

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bg

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Re: Frustrating Jet Catapult gliders
Reply #199 - Jun 25^th, 2009 at 9:33pm

Hi All,
Josh I certainly agree that the Canberra has potential although mine had inadequate stab area for the short TMA and so it did not transition most of the time and would dive in if disturbed by turbulance. I need to try another.

Another great jet cat candidate is the Mig 15 ...my Mig consistently hits 40 seconds and it is warped and therefore very spirally on launch.

My next one is a 18 inch Miles Sparrowjet with is halfway done. I believe this one will be a goa Cool

Bernard

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staubkorb

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Re: Frustrating Jet Catapult gliders
Reply #200 - Aug 21^st, 2009 at 6:04am

Took my Viggens (#1 and #135) out last Wed. afternoon to (try) and get them into trim for the current postal.

The flights of the original sized #1 were without any real issues (except duration), getting around 15 to 22 seconds - flew it more for kicks. �The enlarged #135 (yeah, I've built 135 of the buggers Shocked

) was giving me fits - just wouldn't work - till, in desperation, I gave it a full pull shot STRAIGHT UP! �Two vertical barrel rolls and she popped out into a VERY nose down left glide. �NO amount of "up" trim helped, so a glob of clay got slapped on the tailpipe for another go - and GO she did. �Fairly consistant flights - all in the lower 20 second range, but the model did much better last year.

The biggest problem is that at least 2 out of 5 tries result in the model stalling at the top and doing the "delta tumble". �The VIGGEN has a HUGE amount of side area, so the rudder/fin might be a bit small. � I'm in the process of making a mod. to the rudder.

Another thing I'm trying out is an variable angle (auto) foreplane. �The glide decalage causes the plane to really zoom (loop) on launch. �The choice of setting the foreplane at 0� and flying as a flying wing did not work due to the reflex needed in th main wing. �So far, the results are inconclusive.

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staubkorb

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Re: Frustrating Jet Catapult gliders
Reply #201 - Oct 27^th, 2009 at 1:50am

I made up a new kitty for the CMAC e-postal that BG is sponsoring. �I'd like to try to place decently without having to rely on the bonus points that the VIGGEN brings, so I made up a F9F Cougar.

7-1/8th inch wingspan, length - 10-1/4", weight without clothes but flyable - 9.3 grams.

Plan to take it to the field in an hour or so, if it doesn't rain.

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Re: Frustrating Jet Catapult gliders
Reply #202 - Nov 30^th, 2009 at 5:50pm

Wayne Nagy wrote on Apr 28^th, 2008 at 2:57pm:

Sorry Josh, I think I found out your secret project...

Call me crazy (take a number), but, with the Swiss Yves Rossy-"Jet Man"-just in the news for ending up in the drink trying to cross from Morocco to Gibralter, has anyone got a three view? I don't see how it wouldn't qualify, it is a man carrying jet

/ He crossed the Channel with it!

Now, could I build a model and actually get more then plummet out of it? I have more doubts then you can imagine, but having read this thread yesterday, it seems nobody else is doing really well.

robert quixote Cheesy

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staubkorb Offline Bugs fly too! Posts: 1069 Roedermark, Ger.	Re: Frustrating Jet Catapult gliders Reply #203 - Dec 1^st, 2009 at 10:08am I dunno... Pres Bruning's rubber powered "Rocky" (flying squirrel) flys quite nicely, even in the glide. A "Jet Man" glider is a similar planform. Would be worth trying, and, IMO legal. Pete
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Steve Price

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Re: Frustrating Jet Catapult gliders
Reply #204 - Dec 5^th, 2009 at 7:39am

Gents not to be seen as a hijack. I am going away for a while and will not be able to build but will be able to cut and sort some parts. I was wondering if there was a good flying cat glider that you all would reccomend? I want this glider to look like a real jet as I will cut out 20 or so 'kits' to do with the boys club upon my return at the local resource center.

Suggestions welcome. We have done a lot of good fliers such as the Sparrow by Lloyd Shales but I would like to have a "looks like a Jet" plane to have the boys try next time.

Steve

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JoshuaF

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Re: Frustrating Jet Catapult gliders
Reply #205 - Dec 5^th, 2009 at 12:01pm

Steve,

The best ones I've worked with are the BAC Canberra and Gloster Meteor. Another very good one is the Hawker Hunter, which is a pretty simple build and flies much better than one would expect. The Canberra is a really good, stable design, but the Meteor appears to have the best top end performance. Trouble is that the Meteor takes much longer to trim for efficient flight. Easy to get it flying ok, but anything more than 20 seconds takes a long time to achieve consistently. Mine was capable of about 40 sec, but I had to limit the power because the wings were too weak. Could probably do 50 sec with the right tweaks. It was extremely consistent once trimmed and had the most efficient climb and glide pattern of any scale CLG I've ever worked with.

Another fun one is the Jet Provost. Easy to get it flying ok, but not a very efficient glide pattern. It thermals great, though. Mine did over 8 minutes one time.

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Steve Price Offline Posts: 934 Kingston	Re: Frustrating Jet Catapult gliders Reply #206 - Dec 5^th, 2009 at 12:35pm Thank you very much
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staubkorb

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Re: Frustrating Jet Catapult gliders
Reply #207 - May 19^th, 2010 at 12:00pm

I've just completed a new catapult jet/rocket �model of the Yokosuka MXY 7 "OHKA" manned bomb (no, NOT misspelled). �This "aircraft" was mis-named by the U.S. military as the "BAKA" �Kamikze bomb.

I built the model from a .jpg plan supplied thru an Argentinian modeling site by an HPA member from Uruguay. �I cropped the parts views and saved as an 8" span .pdf to make things easier and prepared templates.

The jpg was a bit distorted, making the wing and stab halves unequal. �I did the fold and cut equalization trick using th long side as a master. �The resul is shown below.

Backyard tests have been satisfying, but the weather has been too yuckky to try any real flights at the field.

Might be a good candidate for L1 rapier power?

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staubkorb

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Roedermark, Ger.

Re: Frustrating Jet Catapult gliders
Reply #208 - May 22^nd, 2010 at 5:31pm

I stumbled across this manned version of the WW2 German "Buzz-Bomb" a few days ago while searching for more data about the OHKA and the "Baika" (BAKA) piloted bombs. �The general proportions cried out "catapult jet" so I sketched up a plan and built one.

I fudged the area of the wing and stab, adding about 10%. �After a bit more digging on the Web, I found that the later (of a total of 175) Reichenbergs (R4 and 5) had ailerons with the corresponding increase in area, so the model is almost to scale proportions. �I was a little worried about the "rudder" - the actual vert. stab was definitely too small for a close coupled glider, but the lateral area of the Argus pulse jet in profile might be too much. �That, plus the added weight of all that stuff behind the CG had me thinking of great gobs of lead IN SPITE of the long nose (I wasn't too far off base). �I made sure to use the LIGHTEST wood I had for the "jet" with the completed airframe coming out at a fairly light 5.7 grams - in flight trim with NO finish, it's at 8.4. �Still not TOO bad for a fun model

The initial glide tests yesterday, stilled my biggest worries - the thing flew. �The first ten catapult launches also went well on low power but with a wierd pattern that I STILL can't describe. �The glide �was stally, but not severe and the glide turn was extremely large. �The miniscule vert. "stab" works, but with more offset than I'm used to. �The evening humidity took its toll, causing the V1 to literally STOP flying!

The monkey in the middle of the trio (with the BIG clump on the nose) is the Reichenberg.

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Re: Frustrating Jet Catapult gliders
Reply #209 - Jul 26^th, 2010 at 6:16pm

About 15 years ago, a local FAC club was doing cat jet at their local contests. They used the 2 meter pole with about a 3' loop. I built an F-84 with the straight wing that did all richt, but didn't quite have enough dihedral for good transition unless the launch went just right concerning launch angle and bank. The design came from an old whip powered article in an old American Modeler. Someone else had a swing wing F-111 that flew quite well, as long as the wings extended evenly.

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