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Author Topic: Double Star 54  (Read 1602 times)

Walter Hicks

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Double Star 54
« on: April 18, 2012, 05:49:48 PM »
A question for you Double Star 54 users. I have an old plane that has gained some weight 61.5 oz, 630 sq inches . I currently have a 12x6 rev Up which actually pitches less than 6 and a little more than 5 on the other blade. Engine runs fine until about half way through the flight  and it gets lean.

Clunk tank , proven plumbing, Power master 10- 22 fuel, Sig Glow Plug per Tom Dixon. This is not a new engine well broken in. It has a Chipmunk cowl so I had to extent the Needle Valve with cooper tubing and a slot car pinion gear. The engine is not at all lean at take off @ 8200 rpm, Tongue muffler as supplied with engine.

Q#1 - Possible this is too much prop?  Too much load on the engine for having to haul around the overweight Imitation/Chipmunk?

Q#2- The longer Needle Valve vibrating excessively? Prop is carefully balanced.

I do not have Armour All in the fuel yet , will add this next flying session.


Q3 - I would like to keep the 12" diameter if possible , by thinning the blades of the Rev Up will that reduce the load on the engine .

If not anyone got any good 12x5 or 6 Eather props for sale .

I have one Eather 11.5 x 5.5?  I will also try that one .


I will check the head bolts, backplate bolts, again, they are tight , the Imitation has an RC mount and that is also tight.


Any of you that use this motor please chime in.Thank you
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Offline Steve Schlesser

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Re: Double Star 54
« Reply #1 on: April 18, 2012, 06:52:42 PM »
Walter,
 On my ds 54 I use a rsm 12x5.5 and on the other one an apc 12x5. Tongue muffler holes drilled out to 1/8 ( 10 holes) on the  tube mufflers I added 9  1/8 holes.
 
  My  planes were just under 60 oz. I also cut the props to 113/4.
This worked for me. Good luck.
Steve
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Offline Bill Little

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Re: Double Star 54
« Reply #2 on: April 19, 2012, 10:09:40 AM »
Hi Walter,

It does sound like you could possibly be having a heat build up problem.  Cutting down the prop a slight bit might help, or adding a bit more oil to the fuel. ???

I hope you get it sorted out!

BIG Bear
RNMM/AMM
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Offline Dennis Toth

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Re: Double Star 54
« Reply #3 on: April 19, 2012, 11:21:20 AM »
Walter,
I fly with the guy who did a lot of the development work on the DS 54 Roy T. One quick test is to drop the nitro to 5% and see if that does it. If it does and you want more power you need to make some other changes. You didn't mention what size venturi you are running. Roy's 54's are rock solid. On setting up a new ship he will start with 10% nitro fuel, 23% oil (1/2syn & 1/2 Castor), 11 1/2 x6 prop, set for around 8500 rpm (63 1/2 ft lines) solid 4cycle. On rare occasion the motor has done just what you described. The first thing Roy does is to check that the needle valve collar is tight and the spray bar is sealed on the sides of the venturi. Next he would change the venturi one size smaller (going down at 0.005" increments). I believe he runs about 0.280 to 0.275" to start. If that doesn't do it add one head gasket. Roy always runs the tube muffler on his DS's. The tube muffler is a unique design with two chambers and some internal baffles. It is designed to give a certain back pressure that helps hold the motor in the power range. You might consider switching to it, Tom Dixon should be able to supply it. Take it one change at a time and you will get the DS that runs strong and solid, they run best in a solid 4 cycle and pull as they are loaded.

Best,         DennisT
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Offline Steve Fitton

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Re: Double Star 54
« Reply #4 on: April 19, 2012, 01:22:58 PM »
I used to have issues with my DS 40 and DS 50 slipping into a constant two stroke in the square eight.  After lots and lots of fruitless tinkering with props, fuel, mufflers, venturis, plugs, head shims, etc, I finally let Eric V and Brad Walker twist my arm into running a PA spraybar and needle valve in the motors.  That finally fixed it.
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Walter Hicks

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Re: Double Star 54
« Reply #5 on: April 19, 2012, 06:36:12 PM »
Thank u all for the responses. I had this engine on a Tutor II for our local ARF Off contest and it ran like a Top. I will Start with 5% Nitro and

Drop to 11.5 diameter prop.
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Offline Bill Hummel

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Re: Double Star 54
« Reply #6 on: April 20, 2012, 08:59:41 AM »
Hi, Walter, we've had success with the 40 BB and 54 BB Double Stars.  We use Powermaster regular fuel(not GMA), the ball bearing Double Stars like less oil. Also, they are very sensitive to head shims, and were originally set-up for no/low nitro.  Don't be afraid to add 2, 3, possibly even 4 shims to get the run to
settle down. On the 54, the .285 venturi seems about right here in the northeast, but might not be the best for where you are.  A little "tuning" with venturi, head shims, and props will get you to a wonderful stunt run!  Contact me if you need more details or options...
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Walter Hicks

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Re: Double Star 54
« Reply #7 on: April 22, 2012, 10:24:58 AM »
Thanks again, for all the input. I changed the NVA to PA and will test today.
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Walter Hicks

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Re: Double Star 54
« Reply #8 on: April 22, 2012, 07:44:59 PM »
Problem solved. It appears that the 12" props , did not like the DS 54. 11.5 no problem, Now using 5% nitro and PA needle valve assembly . Runs like a top. Thanks for all you input.
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Offline Steve Helmick

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Re: Double Star 54
« Reply #9 on: April 23, 2012, 03:29:24 PM »
When PW was running Saitos, he had some weird runs with one, using the DS produced Dixon venturi.  Until he took a look at the spraybar and discovered there was a burr at the drilled hole. I asked him how he fixed the spraybar..."Threw it out!" Remember that DS makes some of the Brodak engines, so if your DS or B. doesn't run consistently, try a ST, ST Clone, or PA NV Assy. It could be that simple! I have an early DS .60bb and love...but I never did use their spraybar/NV. I like the PA units real well.  y1 Steve
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Offline Steve Fitton

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Re: Double Star 54
« Reply #10 on: April 24, 2012, 11:52:19 AM »
Quote from: Walter Hicks on April 22, 2012, 07:44:59 PM
Problem solved. It appears that the 12" props , did not like the DS 54. 11.5 no problem, Now using 5% nitro and PA needle valve assembly . Runs like a top. Thanks for all you input.

Glad to hear its doing better!
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Steve

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