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Engine basics => Engine set up tips => Topic started by: scott matthews on January 14, 2012, 08:44:22 PM
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Hello everybody, just received my Magican kit from Brodak and was wondering which Super tigre engine would you use to power it? I have 3 Super Tigres the first one has A G21 marked on the case I was told that this was there stunt engine of the day, the other two have a C35 marked on the case . The C35's do have a small ridge on the top of the piston surface that I think is the baffle.I did a search I think this is the baffle that some folks are referring to.Which one is the better engine for stunt flying or can you use ether type?Also they are not completely assembled, their ventures are in the boxes, would you start the with smaller of the two sizes and see how they run? One last thing, I was told to start with a 9X5 prop but I am not sure what range of props these engines can handle ,because I have no instructions sheets.
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the ones marked C will be the best stunt engine. The smaller of the venturis would be the best one to run. The G21 motor if it is a 35, is probably the combat motor.
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How big is the ridge on top of the piston? As I recall, the baffle (stunt) version has a baffle about 1/8" high.
As for the G.21, look in the little circle in the V on the side. That tells the displacement. If it is a .35, it is an old combat engine that you can sell for enough to buy a good modern stunt engine. Running one of those in a Magician would be like using a vintage Ferrari for a school bus: it's not well suited for the job and would be more valuable elsewhere. Among the .35s, the one with no means of attaching mufflers is the best, the one with a post in the center of the exhaust is next best, and the one with ears on the side of the exhaust is useless. Other G.21 displacements were .29, .40, and .46. Stunt people like the .46 and might give lots of bucks for one.
If it's a new .35, let's talk.
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Thanks Howard for the advise, it appears that I have one of each version that you described.Unfortunately the engine without the web in between the exhaust port is seized up pretty good so I trying to break it loose with some Nitro Force engine cleaner.If you have some good secrets to break this engine free can you pass them along. Also does Sig 10% fuel with 20% oil work in these motors or do they need more oil and how much?
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Hi Scott,
As has been said, the plain bearing engine with the big C on the case and the baffle is the one for stunt. Smallest venturi to start with. 10-5 to 10-6 prop depending on how much of a 4 stroke you want it to run in, and how fast you want to fly.
about 25% TOTAL oil. (doesn't have to be ALL castor.)
BIG Bear
RNMM/AMM
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Hey Bill, I have been having good results with Sig 10% Champion fuel with my modern engines , do you think Sig's 25% caster and 10% nitro fuel would be a good fuel choice? Or is there something else that people prefer for older engines?
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Hey Bill, I have been having good results with Sig 10% Champion fuel with my modern engines , do you think Sig's 25% caster and 10% nitro fuel would be a good fuel choice? Or is there something else that people prefer for older engines?
Hi Scott,
I just got "schooled" by Randy Smith on correct fuels for these engines. I have some Sig 25% all castor and he recommend adding 3 3/4 oz. of Klotz to it. It doesn't really need to be ALL castor as was thought in olden days.
BIG Bear
RNMM/AMM
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The plain-bearing engine should not be run with synthetic oil, although a little wouldn't hurt. Jeff Rein had a .35C on a carrier plane at the 1973 Nats. He was running synthetic-oil fuel, and getting awful runs. We noticed a pretty, sparkly metallic oil streak on his wing: his crankshaft bearing. Harry Higley fixed him up with some castor-oil fuel, and Jeff won the event.
Dan Bregar and Bob Mellen put me onto some modified soybean oil for G.21s (Greasy Kid Stuff, for those who remember it). It only took 12%, but we used 15%, with no other oil. It had the additional advantage of being completely soluble in nitromethane. Castor oil only works up to about 30% nitro.
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Right don't use all synthetic oil fuel such as many of the RC sport fuels, however I ran my G-21 35s with partial synth. in a castor Synth mix with very good results and never had an oil related failure.
I had many many ST 35s too ,so I will stick by my statements about this... and I am NOT talking about using 14% total synth as found in some RC sport fuels.
A blend of castor and good synthetic oil at 25% works very well
Randy
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Hey Randy, If I go with Bill Littles advise on using Sig 25% castor fuel with 3 3/4 Klotz oil which Klotz oil do you use? They have three diferrnt types at Tower Hobbies, Benol 2,Techniplate or Super Techniplate?
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Hi you can use the techiplate
Randy
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Scott
Having recently built the Brodak Magician kit, and flying it all 2011 season, I have to say that a modern 25 engine is more appropriate for this kit. But having said that, if the Super Tigre engines are all you have available, you could use them. I would suggest you fiberglass the fuselage wing joint well, to minimize stress cracks from the engine, whichever one you choose.
Have fun !
Dan
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Hello Randy,I forgot to add the most important question.When you add 3 3/4 onces of Klotz oil is that per gallon of 25% castor oil fuel? If you were adding Klotz to a quart size container how much would you use?
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Hello Randy,I forgot to add the most important question.When you add 3 3/4 onces of Klotz oil is that per gallon of 25% castor oil fuel? If you were adding Klotz to a quart size container how much would you use?
Hi Scott,
The 3 3/4 is per gallon so about 1 oz. per quart.
BIG Bear
RNMM/AMM
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Hello Randy,I forgot to add the most important question.When you add 3 3/4 onces of Klotz oil is that per gallon of 25% castor oil fuel? If you were adding Klotz to a quart size container how much would you use?
Divide by 4 3.75 / 4 = .93 or just use just short of 1 ounce. it won't hurt if you just add 1 ounce per qt
Randy
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Don't force that seized up engine! Chances are it is Gummed up with Castor...Put it in the oven at abt. 300/350 degrees and it'll loosen up. Wait for it to cool down some then add some after run.
W.
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Engine came loose with Nitro Force, and has good compresssion. Now to build that Magican so that I can use this engine when the weather breaks.Are there any other fuel companies besides Sig that sell fuel with higher levels of castor or can some members share their fuel formula"s for older engines.
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You may want to remove the backplare, wash out the engine with fuel or WD40 then turn the shaft both ways, make sure the rear bearing is OK and that it is turning smoothly, I have seen them with the crank turn inside of the inner race of the bearing instead of the bearing turning properly
Randy
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Engine came loose with Nitro Force, and has good compresssion. Now to build that Magican so that I can use this engine when the weather breaks.Are there any other fuel companies besides Sig that sell fuel with higher levels of castor or can some members share their fuel formula"s for older engines.
Hi Scott,
You want to end up with 25%-28% total oil with most castor, Randy says that and I will not argue with him about these things. ;D
Bill
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A ST that was that gummed up more than likely has a froze wrist pin. The pin get frozen to the piston. You can not tell by hand flipping it.
Ed