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Engine basics => Engine set up tips => Topic started by: Paul Allen on April 03, 2013, 02:45:27 AM

Title: Torpedo 40
Post by: Paul Allen on April 03, 2013, 02:45:27 AM
Guy's
       Can anyone shed some light on the engine in the photo, is it usable
as a stunt motor?
thanks
Paul
In OZ
Title: Re: Torpedo 40
Post by: Jim Thomerson on April 03, 2013, 06:55:12 AM
I've flown the 4011, a later model, on several airplanes and really like it.  Try an APC 11 x 5 as a starting point.
Title: Re: Torpedo 40
Post by: Robert Zambelli on April 03, 2013, 08:04:16 AM
I made a slight modification to one - I radiused the combustion chamber out to .45, leaving a .04 squish band.
Also, I used an ENYA NVA and removed all the paper gaskets.

Although a bit thirsty, it ran and sounded like a Fox 35 on steroids!
Nice engine and very smooth.

   Bob Z.
Title: Re: Torpedo 40
Post by: EddyR on April 03, 2013, 09:22:49 AM
Many moons ago I used those in FF models and they turned a 11x4 at 18,000+. Had it in a Starduster 900
Ed
Title: Re: Torpedo 40
Post by: Steve Helmick on April 03, 2013, 06:15:30 PM
I made a slight modification to one - I radiused the combustion chamber out to .45, leaving a .04 squish band.
Also, I used an ENYA NVA and removed all the paper gaskets.

Although a bit thirsty, it ran and sounded like a Fox 35 on steroids!
Nice engine and very smooth.

   Bob Z.


That cast head version (early production) had a wedge head. The barstock heads were hemi/squishband design. The cranks tend to snap at the front bearing, the aluminum ring around the crank disc sometimes came loose,  as did the pressed-in crankpins. The Dykes rings worked great, until they didn't work right anymore, and the plastic wristpin pads were not real durable. The later front end (#4050 & 4055 series) was much more durable and a lot heavier, putting it up to about 10.5 oz. In short, I would not bother with it, but if you want to use it in a plane where you can easily swap in something else, it could be fun. The Starduster 900 would be a good choice!  H^^ Steve
Title: Re: Torpedo 40
Post by: Paul Allen on April 03, 2013, 11:27:31 PM
Steve
         Yes, the head is a wedge type, no gaskets used in this engine, its new
never been run, so I will keep it for display. Why did it have the ring around the crankshaft?
Thanks
Paul
In OZ
Title: Re: Torpedo 40
Post by: Steve Helmick on April 04, 2013, 12:04:16 AM
Paul, the aluminum ring on the crank is for crankcase "stuffing". The idea is to provide better "pumping action", but in fact it doesn't do anything, and is sometimes a source of grief. I never had that problem, but had all the others...in spades. What happened was that after a typical combat match crash (with the .35 version), the crank would soon snap, there would be a spectacular shaft-run, the crankpin would come out of the crank a bit, grind up the backplate, and eat the piston/cylinder.  The factory was really quite good about fixing the broken stuff, but it was a hassle to be wondering when you'd get your engine back, and then have to break-in again. Besides, fuel was around $4/gallon, ya know?!   H^^ Steve 
Title: Re: Torpedo 40
Post by: M Spencer on April 05, 2013, 06:25:52 PM
Some have ' P ' stamped on the front of the ( wedge 0 head , for Pylon . . . .

The rat Racer GRMZYPH used these things .

Had one in a 57 Oz 57 in. aerobatic model , dark red . Scarlet Even .
Flying it at dusk it was a notch lean . Wound needle in , 1 7/8 turns.
Right . Set it to Two . Except somehow it was one . . .

11x 5 master or zinger was good .

Sounds like you need to build a Rat Racer for it though .  %^@ H^^
Title: Re: Torpedo 40
Post by: Timothy Payne on April 06, 2013, 01:14:09 AM
I've just aquired a K@B Torpedo 29, (it's soaking in paraffin at the minute!). This is a really old motor from the 50's I think. - Would I have to use a sloppy rich fuel mix as with my Foxes?

They like alot of nitro don't they; 25%+.
Title: Re: Torpedo 40
Post by: bob whitney on April 06, 2013, 05:21:01 PM

is it a 3 bolt or 4 bolt backplate  if 4 bolt dose it have a silver or green head  the silver head ( 29R ) was a racing engine ,the green head (29S ) was not one of their more powerful engines
Title: Re: Torpedo 40
Post by: Timothy Payne on April 09, 2013, 01:27:36 AM
The motors a 3 bolt with a green head. Turns out the liner was fitted the wrong way round (transfer port higher than exhaust port). I sorted this out, but it will only just run due to next to no compression! - Do you know if any piston for a 29 will work or would I be best to have one made? (Bore size is 0.724")

Any ideas would be appreciated,

Tim
Title: Re: Torpedo 40
Post by: Jim Kraft on April 09, 2013, 08:08:08 AM
Clean the piston up good with lacquer  thinner, heat it up with a butane torch until starting to turn red, and drop it in a can of motor oil. Have plenty of oil in the can and do it outside. It will smoke a bit. That may grow the piston enough to get compression back. It has worked for me. To heat the piston I put a piece of music wire in a vice and put the piston on top of the wire. Try to heat it as evenly as you can.