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Old Nov 12, 2000, 11:55 AM
Registered User
Texas
Joined Aug 1999
5,110 Posts
Catapult launcher for 1/12 scale planes

First hand launch try:

I tried to hand launch my FW-190. It has a wing loading of about 22lbs per sq/in. The motor I have in it put out about 115+ watts per pound of thrust. I thought that the power of the motor could save me from a crappy throw.

Anyway, with that low wing, itís hard to hold and throw. I tried to throw it straight, but when I threw it, it came out at too steep of an angle when it came out of my hand prematurely. It climbed up, stalled, and then crashed into the ground from about 20 feet.

Is this a two-man job?

Also, does a plane like this require a running start?

BTW, the only real damage was a minor crack in the cowl and a severed nylon bolt. The wing and fuse were damage free except for two cowl screws that popped out. I'm very impressed with this plane to say the least. I thought I was going to pick up a pile of balsa, but this plane and wing are very well built and very strong.

Second hand launch try:
I adjusted my grip and I was able to hold it better. I tried to hand launch three more times today and I meet with failure each time. Fortunately, where I launched it was muddy and over-grown with tall grass and weeds. I have no damage to report, but I did get mud on the wing. Yuck.

I suppose I really need a catapult!

I saw plans for one, but I really don't want to build one. (Yes I'm feeling lazy.)



Does anyone know if a catapult like this one is being built and marketed to impatient RC'ers like me?

p.s. I tried to launch on my 7-cell pack. I may push my luck and try my 8-cell pack. That extra cell may give the "umph" I need. Does anyone think it is even possible to hand launch a 1/12 scale plane?

I really need to get this baby in the air so I can finish my review. Would anyone like to come down and help me launch this bad boy?


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Old Nov 12, 2000, 01:16 PM
Stupid gravity!
docphi's Avatar
Trinity, FL
Joined Jul 1999
1,516 Posts
The Electric Jet Factory has a catapult system.
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Old Nov 12, 2000, 01:56 PM
Registered User
Texas
Joined Aug 1999
5,110 Posts
I saw it. It is really a bungee system with a base to launch from. No offense to EJF, but it is a little too price as compared to other bungee systems.
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Old Nov 12, 2000, 02:52 PM
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Ft Meade, Maryland
Joined Oct 2000
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I still don't think it would fly - 1.5lbs(22ozs)/sq in is still a bit much . 22oz/ft? Don't worry, not even NASA can get it straight
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Old Nov 12, 2000, 03:49 PM
Registered User
Texas
Joined Aug 1999
5,110 Posts
Your right. 22oz/sq ft.

245sq/in (1.7 sq ft)
~38oz (~2.375 lbs)

~22.35 oz/ft^2 or .15oz/in^2

Sorry for the confusion
Dave
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Old Nov 12, 2000, 04:05 PM
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ScottS's Avatar
Houston,TX
Joined Mar 2000
1,217 Posts
I don't see any reason why the type of system I use to launch the picojet wouldn't work. You would need to launch with the motor off or figure out another way to attach the bungee, however I think the EJF system works the same way. With enough pull on the bungee launching with the motor off isn't a problem anyways, I have accidentally launched the picojet with a totally dead battery and a made a complete circuit to land.
I got the bungee from http://www.hollyday.com/
the rest of the stuff from the local hardware store.

[This message has been edited by ScottS (edited 11-12-2000).]
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Old Nov 12, 2000, 07:58 PM
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Ft Meade, Maryland
Joined Oct 2000
444 Posts
Sorry, Dave, I was just messing with you. I wasn't trying to be snide. I am suprised (or however you spell it) that no one has added a foot pedal to the bungee for those few brave soloist. A stomp and launch type system. You just need an L shaped piece of wood with top of the L hitting the trigger and the bottom of the L about 3" off the turf. I might build one just to see if it will work. Darn tools are still in the mail.
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Old Nov 12, 2000, 08:51 PM
H301 Libelle Pilot
Dr. Jet's Avatar
Oceanside, California
Joined Sep 2000
1,249 Posts
The EJF launch system may be a little pricey, but look what you get. The bungee tubing is not cheap. You get a lightweight, easy to transport and carry unit designed by "Tommy" that has been thouroughly tested (by Dr. Jet no less ), complete and ready to launch in 5 minutes. Yeah, anyone can build one, but why bother? Robert can probably custom order launchers to suit your particular needs at little or no additional cost (depending on complexity). The latest versions have carrying handles and snaps to hold the spikes during transport. The bungee is wrapped aroung the pedal for transport. the stand also serves an airplane stand for assembly and set-up. Simple, convenient, and consistent launches every time. This thing works and it works well. I've launched numerous low wing WWII fighters, my T-33, A-10, A-4, and now the JePe F-16 with it.

I like mine, can you tell?
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Old Nov 12, 2000, 09:24 PM
Mike Swan
Oroville, California, United States
Joined Oct 2000
372 Posts
The unit you have pictured is i believe from the plans available through arkill on www.scalecombat.com (kits and plans) theres alot of good information on catapults,but if you dont want to build try warbirds ltd, same site,most are home made copys of somebody elses,its pretty much the standard for combat flying,makes life alot easier when your alone for that test flight. Mike
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Old Nov 12, 2000, 10:42 PM
Registered User
Texas
Joined Aug 1999
5,110 Posts
V.,
I didn't take your post in a bad way. I just got sloppy with mine. I forgot to engage my brain before my fingers.

D.J.,
That launcher still looks pricey to me. Even so, I think I may prefer a catapult vs. bungee launcher. I've heard mixed reviews on bungee systems.

k.b,
Yes that is the catapult launcher from Air Kill. Would you happen to have a link to War Birds Ltd.?

http://www.rccombat.com/sections/man...s=139&Users=49
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Old Nov 12, 2000, 10:46 PM
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Texas
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k.b,

Never mind. I found it.
http://www.warbirdsltd.com/photo.htm



Catapult Launch System Kit - Consistent, Lightweight, Portable $45.00




[This message has been edited by dave_lilley (edited 11-12-2000).]
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Old Nov 13, 2000, 12:30 AM
Registered User
Ft Meade, Maryland
Joined Oct 2000
444 Posts
I'd love too, but at 22lb/sq in, I don't think it will fly . I'll be around Ft Hood around the 22nd of February. I think that is a tad past the dealine that you have in mind, and also a bit of a drive.
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Old Nov 13, 2000, 12:44 AM
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Texas
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Damn, I did that again. 22oz.
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Old Nov 13, 2000, 03:03 AM
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NY
Joined Dec 1999
308 Posts
Quote:
Originally posted by Vassel:
I'd love too, but at 22lb/sq in, I don't think it will fly . I'll be around Ft Hood around the 22nd of February. I think that is a tad past the dealine that you have in mind, and also a bit of a drive.
-------------------------------------------------Yes go for 8 cells all the guys in my club fly warbirds with 8 and some ROG
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Old Nov 13, 2000, 01:28 PM
All under control, Grommit!
leccyflyer's Avatar
United Kingdom, Aberdeen
Joined Sep 2000
12,588 Posts
Evening chaps

That Airkill cat looks just the job!
But where can one be had?
I could knock one up for thirty bob.
And wouldn't I be glad?

I've looked at all the plans and kits
On all the combat sites
My problem is a lack of bits
To make the cat work right

My emails to that Wardbirds bunch
Haven't been answered yet
I suppose they could be out to lunch
But I wouldn't take that bet

The problem that I have you see
Is down at our club field
If one was to rig a long bungee
With a pedal that would yield....

Many complaints of hogging the strip
And muttering angry fliers
So a catapult without the length
Of bungee is my desire

If any kind souls know of a site
Where such a thing exists
I'd be eternally grateful and I might
Not have to slit my wrists

I thenk you!

Arthur Askey (1939)

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