Tempest 3D with Viperhead

[tempest]

Hi all :D

I have just brought a Fury Tempest 3D with 4 S9252, Gyro 601 S9251, GV 1 Governor, OS MAX SX H C, MP2 (still waiting for the 690s 185g Radix Blades). :wink:

Here is my problem

I am looking for a Viperhead with dual Glow plug ports but a Friend of my told me I should watch out with this head! He had 1 as well and his OS MAX SX H C never went right. 1 of the glow plugs with the thread ripped out in flight and had to do an auto.

Some People say it is the best Tuning you can ever have for your Motor with no problems. What shell I do? :?

Sorry for my very bad English. I live in Switzerland and I love my Tempest. I don’t want to Crash it just because of a Head that doesn’t work. :oops:

Thanks for your Help :mrgreen: :D

Andrew

[DavidH]

Here in the USA there is a lot of pilots using the Viperhead on the OS 91 and YS 91.

Not saying it can't happen. But I have never heard of anyone with the Viperhead having problem with the glow plug threads. OMI produces a quality product that works very well and enhances the performance of the motor.

I can assure you. If there is any problem with the Viperhead. James O'Neal at OMI will correct any problem that might arise if it is a manufactuering defect.

David

[tempest]

Thanks for your fast answer and Help!! :D

So i will get 1 from Zooms and hope it really works.

Andrew

[DavidH]

Setting the Viperhead up will depend on what fuel your using.
With Cool Power and Power Master 30% heli. You will need (2) .008 shims for a total of .016 in shims. The Viperhead for the OS comes with (1) .008 shim and the stock OS shim is .008. So you just add the one shim with the Viperhead.

If your using Magnum 30% you will need a total of .024 in shims. So you will need another .008 shim. I don't think James is including more than one .008 shim with the Viperhead.

You may have to experiment what shimming works best for your setup. You don't want the motor to have pre-ignition.

David

[tempest]

The Viperhaed does not work really great with the Magnum Fuel. I will go for the Cool Power 30%

Andrew

[sumonzu]

Setting the Viperhead up will depend on what fuel your using.
With Cool Power and Power Master 30% heli. You will need (2) .008 shims for a total of .016 in shims. The Viperhead for the OS comes with (1) .008 shim and the stock OS shim is .008. So you just add the one shim with the Viperhead.

If your using Magnum 30% you will need a total of .024 in shims. So you will need another .008 shim. I don't think James is including more than one .008 shim with the Viperhead.

You may have to experiment what shimming works best for your setup. You don't want the motor to have pre-ignition.

David

I found that .024 in shims works a lot better even with Cool Power 30%. I fly at 3300 feet altitude: does it make sense? With .016 shims my engine runs too hot even with a rich carburetor setting. Has anyone experimented the same situation?

[DavidH]

At 3300 ASL. I don't know if James has had any reports from pilots that are flying at that altitude. But I would think there is some around the Rocky Mountain area that are flying at that altitude or higher using the VH on a C Spec.

At that altitude I would have thought you would need to raise the compression which would actually mean less shims. But I guess you have to do what is working best for you in your situation.

David

[sumonzu]

Hi David, look that 3300 feet is only 1000 meters ASL, not so high. Also the temperature is mild allover the year here in Costa Rica, quite humid by the way.

Unfortunately I never brought my helis at the sea level to see the difference therefore I cannot say if I need less shims or whatever. I have two identical OS 91 C-Spec OMI modified and I noticed a marked difference between the one shimmed with 0.024" and the other that "was" shimmed 0.016": the first one runs smoothly and cool, the second one run very hot and with an irregular minimum.
I'd like possibly to hear from anyone that has had the same experience.

Marcello