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Engine basics => Engine set up tips => Topic started by: Steve Helmick on August 12, 2006, 11:47:35 PM

Title: Double Star .40 questions....
Post by: Steve Helmick on August 12, 2006, 11:47:35 PM
I've recently started flying a Profile Cavalier with a DS .40. Any setup info for this engine would be useful. I got it slightly used, but it looks to have a stock venturi, which looks very small. I can make venturii, and expect something like .285" would work better than whatever is in there. It came with an old TF 11-5 paddle blade, and it doesn't work very well at this point, with the venturi it has. The model came from fairly high altitude, so I'm expecting to need a bigger fuel tank. How much fuel do you burn, what venturi bore, at what altitude and how much nitro%? Thanks in advanced, Steve
Title: Re: Double Star .40 questions....
Post by: Steve Fitton on August 14, 2006, 12:03:42 PM
I run mine mostly stock, in a 42 ounce Nobler.  Prop, 10x6 rev-up extra wide, or modified Zinger xtra wide 10x6, extensively cleaned up.  Can also run Powerpoint 11x6 cut down to about 10.5.  Two head shims, Powermaster 10/18 fuel, Sig 003 plug.  Runs about 6:45 at Sea level on 4 oz fuel.  Compared to my DS 60 the 40 is very picky about overheating, albeit many have fixed this it would seem by going to a larger venturi.  Mine still has the stock venturi....


Steve
Title: Re: Double Star .40 questions....
Post by: Bill Little on August 14, 2006, 09:48:32 PM
From Tom Dixon:  add two to three head shims depending on the amount of nitro you want to use.  The DS 40 was set up to run on FAI (no nitro) fuel.  (Tom is the one who has the DS line of engines made and imports them)

I found out that the stock venturi gives less choke area than a stock Fox 35.  If you want anything approaching the power the engine can give, go to a bigger venturi. 

Tom gave me a pro he used on his DS 40 in his Nobler for a while.  It is a 10 1/2 X 5 wood of unknow origin, but probably a bigger Zinger cut down and shaped.

Stock "OOB" they are not much more than a good stock Fox 35, and real finiky if you use any nitro.  With the mods above, you will get a pretty decent "40" out of the deal.  Especially if you like a deep 4-2 run.  Stevie boy doesn't believe what this "old man" (with over 43 years of flying) tells him, but that's what really brings the DS 40 alive.   y1

Bill <><
Title: Re: Double Star .40 questions....
Post by: Steve Fitton on August 15, 2006, 09:48:25 AM
I believe you Bear, just been too lazy to pull the plane off the wall and work on it!  It has been sitting since its last flight at brodaks while I mess with the big planes.  I even have, courtesy of Jim Svitko, a "special" venturi to put in there! #^
Title: Re: Double Star .40 questions....
Post by: Scott Jenkins on August 16, 2006, 11:34:56 AM
Steve,

Sorry can't resist, ".15" lines"  %^ you're gonna need a much bigger engine  #^
Yup, Yup, that's what he said.

Scott
Title: Re: Double Star .40 questions....
Post by: Bob Kruger on August 17, 2006, 05:43:30 PM
I've recently started flying a Profile Cavalier with a DS .40. Any setup info for this engine would be useful. I got it slightly used, but it looks to have a stock venturi, which looks very small. I can make venturii, and expect something like .285" would work better than whatever is in there. It came with an old TF 11-5 paddle blade, and it doesn't work very well at this point, with the venturi it has. The model came from fairly high altitude, so I'm expecting to need a bigger fuel tank. How much fuel do you burn, what venturi bore, at what altitude and how much nitro%? Thanks in advanced, Steve

Steve;

Len Neumann made the venturi for mine, as it was an early one.  I use an old TF 11-5 cut down to 10.5.-5, 10% nitro fuel, 22% lube, one extra head gasket.  It will pull an Oriental nicely on 60' lines - I might be able to add a couple of feet.  Much less vibration than my old Fox 35s.

V/r

Bob