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Author Topic: Would a RATO type model be impractical?  (Read 194 times)
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Larry R.
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« on: August 27, 2019, 09:06:18 AM »

The development of a new Jet-X power unit is interesting, and I do hope the developers succeed, and the new Jet-X becomes commercially viable.  Pending that, I'm wondering whether anyone has built a rocket engine powered model.  The most obvious candidates are the Me-163, the Bell X-1, and some of the early Soviet jets such as the La-152.  A RATO model would have a power profile much like a catapult launched plane....big but brief surge of power to gain altitude for a glide back to earth.  The rocket engines are widely available, at least in the U.S., and come in a pretty wide assortment of sizes.  They are a bit pricey.  I suppose the simplest model would a tube with a wing and tail surfaces.
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Yak 52
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« Reply #1 on: August 27, 2019, 09:30:14 AM »

Josh Finn makes rocket launcher gliders:
https://m.youtube.com/watch?v=67fpOi5i9mM

He posts here and also has more on his YouTube channel 'jwfinn'. Hopefully he will see this and be able to help. You are right about the profile, very powerful and a short time when compared to Rapier or Here's motors.

Jon
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billdennis747
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« Reply #2 on: August 27, 2019, 09:55:14 AM »

Don´t space modellers already do this? Rocket powered gliders with RC
But if you mean RATO as I understand it, Derek Knight in the UK did it some years ago with a Barroudeur (me neither - google it). The electric ducted fan model sat on a trolley with two big Rapier motors. The whole lot rocketed across the runway with the model lifting off at the edge. The trolley hit the rubble, bounced in the air and returned whence  it started, disappearing up the shorts (left leg) of Andrew Hewitt. Much smoke and dancing about. I can see it now.
I´m guessing that´s not what you have in mind?
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Larry R.
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« Reply #3 on: August 27, 2019, 10:35:25 AM »

Hi, Jon and Bill

First, I have to say the Josh Finn rocket powered, folding wing gliders are pure genius.  Wonderful video.

What brought this thought to mind were two forum threads that I find interesting, the discussion of the new Jet-X effort, and cata-jets.  Full fuselage EDF jets are not new, neither are full fuse Jetex (or Rapier, etc.).  Full fuse catapult launch may not be practical (although bungee launched jets could be, I think).  The new Jet-X engines appear to be similar to the Estes engines, i.e., a rolled paper, single use engine, but with a slow burning solid fuel.  If used with a proper launch system to keep hot exhaust gases away from your hands and arms, this could be a welcomed modeling resource.

In the meantime, as the new Jet-X is perfected and becomes available, I was wondering about the currently available rocket engines.  I noticed in the Hip Pocket Plans Gallery an R/C model of a Soviet rocket powered fighter, which uses the larger Estes motors.
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strat-o
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« Reply #4 on: August 27, 2019, 12:18:33 PM »

If you look at world-class power models flown in FAI competition, they have flight characteristics that is almost rocket like:  In FAI Power you have a relatively short and powerful burst of thrust.  Since the goal is to get as much altitude as possible in a very short time, the climb is vertical.  Of course, the climb is rapid as possible because you have a strictly limited motor run.  Most competitors use what is called a bunt which is a carefully timed rapid deflection of down elevator at the optimal moment in order to kick the aircraft level and establish a stabilized glide. 

I realize your focus is scale but I bring this up because there may be some opportunities for cross-pollination of ideas.

Marlin
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« Reply #5 on: August 27, 2019, 02:56:17 PM »

But if you mean RATO as I understand it, Derek Knight in the UK did it some years ago with a Barroudeur (me neither - google it). The electric ducted fan model sat on a trolley with two big Rapier motors. The whole lot rocketed across the runway with the model lifting off at the edge. The trolley hit the rubble, bounced in the air and returned whence  it started, disappearing up the shorts (left leg) of Andrew Hewitt. Much smoke and dancing about. I can see it now.
I´m guessing that´s not what you have in mind?
I have shots of the actual incident somewhere ... but here's a couple of shots from another flight.
Attached files Thumbnail(s):
Re: Would a RATO type model be impractical?
Re: Would a RATO type model be impractical?
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fred
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« Reply #6 on: September 08, 2019, 03:39:15 PM »

I've seen a couple or More? RC Me 163  Scale models of 1;12th and larger size that were Estes type rocket motor powered. 
Rapid  climbs to a few hundred feet then a controlled glide around..a couple of aerobatic delights,  before landing. 
Very convincing.
I suspect Motor running  costs would mount though.
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