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Building Tips and technical articles. => 1/2 A building. => Topic started by: Duke.Johnson on February 11, 2013, 01:55:09 PM
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I just picked up a new in box Thunder Tiger .070 and I'm looking for the ideal 1/2A stunter. I've never run a TT .070 and don't know anything about them. Are they good engines? Any ideas on a great sunter?
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Hi Duke. I can suggest the plane for sure but don't know who might have plans. The Fox Stunt Runt was designed around Duke Fox's .07 stunt. A neat little motor but a great little stunt ship. Rather large as I recall, maybe 250-270 sq. in. Built up wing and built up box fuselage. This flew wonderfully in lighter wind and 42 ft lines. It had a 'sky hook' on the outboard wing, sort of a winglet thing to catch air and pull the plane tight on the lines. If somebody can come up with plans this is a 'Gootun'
Dave
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I found a picture of one and I like the looks of it except the sky hook. I have been thinking of the Pinto.
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Yeah the sky hook isn't aesthetic and I was never sure it did much anyway. Think I'd leave it off. I only vaguely remember the Pinto. Dick Mathis I think, right?
Dave
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I never built the Pinto. I would have to assume the weight of the Thunder Tigre would be at least or close to double the weight of the TD. The other problem with engines of this size is the limited prop choices given for them. Keep in mind the engine of your choice is not a 1/2A engine which probably doesn't make any difference. I'm just saying that in your search for a suitable model, you need to remember that the engine your suggesting wasn't designed for those models. Due to some models even suggesting certain sizes for instance: .049-.07 as an example , those designations were for old school engines. Your engine should be able to fly a model the size of a Brodak Jr Lightning Streak. The only example of the Thunder Tigre .07 engine I saw in use had some problematic issues with needle valve leaks. I do remember the owner changing it after frustrating attempts. Ken
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Hello,
I asked about the TT 07 a year or so back. I didn't get an enthusiastic response and people complained about the weight and it not being a proper 1/2 A engine. So I didn't get as far as trying one out. I am not bothered about it not being 1/2A, after all the AP Wasp is too big for 1/2A and people rave about it. That engine suffers quality problems apart from the piston / liner assembly.
Apart from the higher weight, I suspect it may be a reasonable engine. I am super impressed with the TT GP 42 and 25, so the 07 may be similar. Let us know how you get on, I for one would be very interested in how your project turns out.
Regards,
Andrew.
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Hello,
I asked about the TT 07 a year or so back. I didn't get an enthusiastic response and people complained about the weight and it not being a proper 1/2 A engine. So I didn't get as far as trying one out. I am not bothered about it not being 1/2A, after all the AP Wasp is too big for 1/2A and people rave about it. That engine suffers quality problems apart from the piston / liner assembly.
Apart from the higher weight, I suspect it may be a reasonable engine. I am super impressed with the TT GP 42 and 25, so the 07 may be similar. Let us know how you get on, I for one would be very interested in how your project turns out.
Regards,
Andrew.
Andrew,
Sorry to report that the TT07 while nicely executed is a rather anemic performer. Biggest problem is that it can't breathe with it's very small choke area and modest porting. Even dieselizing it did not improve the performance. Another thing to consider is that the carb is part of the engine casting so you have no options on improving any of it's shortcommings. But for what it isn't it is a thrifty steady runner.
Dennis
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Thanks Dennis,
Looks as though you have saved me some time and money. Pity about that, the GP25 and 42 are very well made and excellent performers, pity the 07 isn't as good!
Regards,
Andrew.
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Anyone know motor range for the Pinto? .049-.09? I'm thinking the TT .070 would work if it's not to heavy. I'm not looking to enter it in a PA contest ;D. Just a little fun in the backyard. But them again maybe it would be better on say the baby flight streak.
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Anyone know motor range for the Pinto? .049-.09? I'm thinking the TT .070 would work if it's not to heavy. I'm not looking to enter it in a PA contest ;D. Just a little fun in the backyard. But them again maybe it would be better on say the baby flight streak.
The Pinto was designed by Dick Mathis. And basically, everything that Dick Mathis did works. It is essentially a scaled down Oriental. It has a 34" span, only about 205 sq in so is on the small side of some of the better 1/2A's. It had a Cox TD .049 which works well. The airplane will do really well as long as it does not weigh much more than 11 oz. These things, at that weight can fly surpriingly well in the wind on 50 foot cables, 0.008" diameter.
Keith
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I've been checking around for the motor range and can't find it.
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I've been checking around for the motor range and can't find it.
If you are asking about the size of engine for the Pinto, I guess I did not directly answer your question.
The Pinto is small. It can fly the entire pattern. To fly at its potential, the weight needs to be kept to around 11 oz. A Cox TD .049 has more than enough power for that airplane. You should probably not use an engine that is any heavier. In fact, a better match would be a Cox Medalian .049. A Brodak .049 would probably be adequate, though I think you would be better off with either of the Cox .049's. A Norvell Big Mig .049 would also be more than enough power. A Norvell Big Mig .061 could be used with little weight penalty, but I think that would be almost too much for that small airplane. The Novells are fully capable of doing very well in a stunt design of up to 240 -250 sq. in. but the weight still needs to be kept to around 12 oz.
If you insist on using that .070 or anything in that size, there are few, if any "stunt" designs available to match that. Bob Baron's Barecat was flown with the Cox TD, 40 in. span, 356 sq. in, 14 oz was competitive against Open competition when Baron flew it. It could be flown with a bigger engine, but weight is still a factor. This one is sort of "outside of the box" of conventional wisdom but it works.
Keith
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The fact of the matter, as told to me by Dee Rice, is that the Pinto is a 1/2A Oriental designed by Dee Rice. He gave the plans to Mathis, and Mathis published them.
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Ok. It appears this TT .070 isn't going to make it into a Pinto. But I've been searching the 1/2A threads for ideas and came across the 1/2A auto-gyro thread by John. He's going to send me the plans, he noted the AP engine he used was a bit much. The TT should work well, it just needs to go round and round. I've wanted to build a couple auto-gyros anyways.