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HelicopterAlignT-REX 700N › viper head ?
01-14-2011 04:38 AM  7 years agoPost 1
livninlv

rrApprentice

las vegas,nv usa

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just got a viper head for my 91H align motor and want to know what glow plugs you are using? do you use the same in both holes or do you us different plugs in the two holes? also what shims are you using?, thanks

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01-14-2011 06:37 PM  7 years agoPost 2
jsenicka

rrProfessor

Eagle River, WI

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I use OS8 in both holes, just because that is what I have around.

Shimming depends on fuel you use and field altitude.

Jim Senicka
Team Manager, GrandRC Flight Team

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01-14-2011 06:51 PM  7 years agoPost 3
helismash

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Gloversville, NY - Fulton

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What is the advantage of the Viper head other than more power?

Hey, Who put the ground there!
T-Rex 500/T-Rex 600N FBL/T-Rex 600E PRO/T-Rex 700N/T-Rex 700FBL

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01-14-2011 07:47 PM  7 years agoPost 4
BladeStrikes

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Shelby TWP,Mi

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livninlv
T-REX 700N viper head ?

just got a viper head for my 91H align motor and want to know what glow plugs you are using? do you use the same in both holes or do you us different plugs in the two holes? also what shims are you using?, thanks
You want to shim the head to .016,thats two .008 shims.Run OS8/OS5 plugs in it.Hotter plug gos in the angled hole and glow wire gos on the center/cold plug.When you install the head make sure the angled hole is on the bottom so you can get to the plug.If you install it on the top,you'll need to drop the engine just to take the plug out if needed..

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01-14-2011 08:11 PM  7 years agoPost 5
jsenicka

rrProfessor

Eagle River, WI

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I disagree on a blanket shim recommendation.
Depends on fuel blend, nitro content, and altitude of flying field.

On CY30 I needed .020 to not detonate at my home field in VA right at sea level. But could easily run .016 at my Dad's place at 1800 feet. On Coolpower 30 you could likely run .016 at sea level and go down as low as .008 when you are closer to 1500 feet or so.

Jim Senicka
Team Manager, GrandRC Flight Team

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01-14-2011 08:41 PM  7 years agoPost 6
BladeStrikes

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Shelby TWP,Mi

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I disagree on a blanket shim recommendation.
What works for you might not work for everyone,thats why its good to get other opinions..016 head shims is a good starting point anyways as its better to be safe than sorry.Im sorry if you don't agree.

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01-14-2011 09:40 PM  7 years agoPost 7
PC12DRVR

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USA

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The Align 91H runs great at sea level with the stock shim and head installed. I live at sea level and ran one on CP 30% it ran great.

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01-14-2011 10:28 PM  7 years agoPost 8
BladeStrikes

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Shelby TWP,Mi

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I live at sea level and ran one on CP 30% it ran great.
Same here other than I run WC 30%.Thats why I recommend the .016 shim as the motor runs very happy.Motor had a slight misfire with the stock head shim but runs very smooth with .016 .The OP needs to buy a shim kit and see what works .Good luck ..

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01-15-2011 12:02 AM  7 years agoPost 9
jsenicka

rrProfessor

Eagle River, WI

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.016 is a good start.
My point was depending on oil package, nitro and altitude, he may be able to get away with .008.
You need just enough shim to allow tuning without detonation. Any more and you are losing power.

And at end of day, with a new HZ class motor, I am not sure there is much benefit to the Viperhead. They were very effective on the CSPEC, but less so on the new motors.

I have one on an HZ and two with stock heads, and really don't notice a difference.

Jim Senicka
Team Manager, GrandRC Flight Team

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01-15-2011 12:55 AM  7 years agoPost 10
BladeStrikes

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Shelby TWP,Mi

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^^ Very true about fuel and oil% and I totally agree .

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01-15-2011 04:40 AM  7 years agoPost 11
livninlv

rrApprentice

las vegas,nv usa

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i;m going with CP 30% because thats what the original owner ran. this is a os91H motor thats why i got the viper head, thought it would help. i don't know the differents between the hz head and the h head but i do know that the hz motor has more power the the stock 91h motor. haven't put it on yet because i'm going to run a couple more tanks through this motor, last person to own it said its only had about 5 tanks through a new sleeve,ring and bearing. can someone tell me whats comes stock as far as shims on the 91h motor?, thanks

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01-15-2011 01:10 PM  7 years agoPost 12
jsenicka

rrProfessor

Eagle River, WI

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Stock was a single .008. The Viper head adds bait of compression. Start with .016 (two thick shims). You should be fine.

Jim Senicka
Team Manager, GrandRC Flight Team

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01-18-2011 12:21 AM  7 years agoPost 13
livninlv

rrApprentice

las vegas,nv usa

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whats the differents between the 91h motor and the 91hz motor? thought i read somewhere that the only differents between the two is that one is align and the other is os. does anyone know?, am i going to be able to tell the differents with the viper head on a stock align 91H motor?, thanks

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HelicopterAlignT-REX 700N › viper head ?
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