Prop Bolt Torque?

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ben_beyer · 10-31-2009, 09:50 PM

How much torque should be applied to wood & gf props when tightening the bolts?

Is it different for single bolts & multi-bolt prop hubs?

lazyboyflyer · 10-31-2009, 09:55 PM

CF props 90 inch lbs, start w/ 50, then 60 and so on. Wood props, I don't use them.

flyin4fun · 10-31-2009, 10:04 PM

	Quote: Originally Posted by lazyboyflyer
	CF props 90 ft lbs, start w/ 50, then 60 and so on. Wood props, I don't use them.

I am pretty sure that is "inch" pounds ......NOT foot pounds

STLAV8R · 10-31-2009, 10:08 PM

	Quote: Originally Posted by flyin4fun
	I am pretty sure that is "inch" pounds ......NOT foot pounds

You are correct!

Ramz · 10-31-2009, 10:18 PM

depends...how big is the bolt? is it oiled? what grade is the bolt?...etc. I asked the same question on here a while ago and for my DA170, I was told to torque the prop bolts to 120 inch/lbs. I went out and bought a 1/4" drive torque wrench just for that purpose and it works great.

ben_beyer · 10-31-2009, 10:35 PM

Right now it's for a Brillelli 60cc but I'm buying a DA 150 in the future.

f5air · 10-31-2009, 11:00 PM

on my DLE55 and Xoar 22x8 i apply 45-50 inch-pound.

Tired Old Man · 10-31-2009, 11:08 PM

For the Brillelli 60 it should be 40 inch pounds for a wood prop and m4 or m5 or 8/10-32 screw. Carbon is the same. I'm presuming a multibolt hub. I don't have a clue where an earlier 90 in lb number came from. That's above the max permissible toque value for any of the screw sizes I just noted.

plane · 10-31-2009, 11:18 PM

Wow, have I gone through this exercise. I originally did the Garrett Morrison method of 37in lbs for wood and 40in lbs for carbon. The 37 works great for wood, but I found that 40in lbs for carbon was way to low.

Those numbers were referenced to grade 8.8 bolts which is standard on 3W's. Those bolts can't take much more than 40in lbs. Later I read a thread about this and Jack Strickland chimed in that grade 12.9 bolts (used on DA's) can handle up to 70in lbs.

After losing two carbon props, spinners, hubs I went to 12.9 bolts and torque them to 65in lbs. That finally solved all of my problems.

The new DA170 is a whole new beast so be sure to torque them up to what DA recommends.

My remarks are in reference to 150 class motors.

2walla · 11-01-2009, 12:44 AM

Not the bolts you need to worry about- its the aluminum threads they engage in.. If you are actually looking at a table to pick the correct torque for the size bolts you use, you need to reduce it 30-50%. Thast why you see people using 40 in lb on a bolt that can handle 70 in lb... That is unless you like installing helicoils...

plane · 11-01-2009, 12:49 AM

Helicoils suck...Timeserts my man. BTW, I have never had the aluminum hubs fail, it's always the bolts that break because they came loose from insufficient torque.

zzw26n · 11-01-2009, 07:07 AM

Is the Torque rating in the DA Manual?

STLAV8R · 11-01-2009, 07:56 AM

	Quote: Originally Posted by zzw26n
	Is the Torque rating in the DA Manual?

Ward, here ya go... shows 70. Does not differentiate between wood and carbon fiber.

Bolt Torque Specs for DA motors

Specific bolt
Bolt size
Bolt Type
Inch lbs.

Cylinder Head 50cc
M5x16
Aluminum

65

These bolts to never be reused
Cylinder Head 75cc
M5x20
Aluminum

70

These bolts to never be reused
Cylinder Head 85cc
M5X20
Steel

DA50 Case
M5x20
Aluminum

70

DA100 Case
M5x20
Aluminum

70

DA150 Case/ Mount
M6x80 FH
Steel

145

Stand-Offs DA50
M5x20
Steel

120

Motor Mount DA100
M6x16FH
Steel

150

Carb Bolts DA50
M5x55
Aluminum
8 w/ blue loctite

Carb Bolts DA100/150
M5x50
Aluminum

50

Reed Block Screws
M5x16
Aluminum

35

Prop Bolts .8 pitch thread
M5x(optional)
Steel

70

Igniton Sensor
#4 x 3/8"
Steel

10

Spark Plug
14MM
Steel

60

Exhaust Bolts
m5x16
Steel

100

Prop Shaft Extension Nut
Custom
Steel
38ft. Lbs.

zzw26n · 11-01-2009, 08:02 AM

Thanks John! may I ask where you got the info? I was going to copy it and save it as a Word.doc

STLAV8R · 11-01-2009, 08:41 AM

	Quote: Originally Posted by zzw26n
	Thanks John! may I ask where you got the info? I was going to copy it and save it as a Word.doc

You're welcome Ward. I got it from Jim Cokonis. He said he received it from DA.

You could always double check with DA just to make sure it is accurate and hasn't changed.

A lot of useful information.

10-31-2009, 09:50 PM	#1
ben_beyer Bad-ass Super Contributer! Join Date: Feb 2006 Location: College Station, TX Age: 29 Posts: 2,919 Awards Showcase Total Awards: 1	Prop Bolt Torque? How much torque should be applied to wood & gf props when tightening the bolts? Is it different for single bolts & multi-bolt prop hubs?

10-31-2009, 09:55 PM	#2
lazyboyflyer The good, the bad and the IMAC Join Date: Jan 2006 Location: Wildomar,Ca. USA Posts: 539	Re: Prop Bolt Torque? CF props 90 inch lbs, start w/ 50, then 60 and so on. Wood props, I don't use them. __________________ Comp-Arf 3m Extra 260 IMAC Plane 3DHS 89" AJ Slick EMAC Plane My flying buddy, Rusty Last edited by lazyboyflyer; 10-31-2009 at 10:27 PM.

10-31-2009, 10:18 PM	#5
Ramz Flying Circles Join Date: Jan 2006 Location: New Brunswick, Canada Age: 30 Posts: 353	Re: Prop Bolt Torque? depends...how big is the bolt? is it oiled? what grade is the bolt?...etc. I asked the same question on here a while ago and for my DA170, I was told to torque the prop bolts to 120 inch/lbs. I went out and bought a 1/4" drive torque wrench just for that purpose and it works great.

10-31-2009, 10:35 PM	#6
ben_beyer Bad-ass Super Contributer! Join Date: Feb 2006 Location: College Station, TX Age: 29 Posts: 2,919 Awards Showcase Total Awards: 1	Re: Prop Bolt Torque? Right now it's for a Brillelli 60cc but I'm buying a DA 150 in the future. __________________ Power R/C Hobbies Waco Hobby Stop RC Today Show Podcast

10-31-2009, 11:00 PM	#7
f5air Fly it....fly it. Join Date: Jun 2009 Location: Texas Posts: 2,530	Re: Prop Bolt Torque? on my DLE55 and Xoar 22x8 i apply 45-50 inch-pound. __________________ - OMP Extra 300 100cc - DLE111 - AW Extra 300 50cc - DLE55 - EF Extra 300 EXT 48" - FUTABA 12Z Fly it like it's stolen

10-31-2009, 11:08 PM	#8
Tired Old Man Bad-ass Super Contributer! Join Date: Jul 2006 Location: California Posts: 4,323	Re: Prop Bolt Torque? For the Brillelli 60 it should be 40 inch pounds for a wood prop and m4 or m5 or 8/10-32 screw. Carbon is the same. I'm presuming a multibolt hub. I don't have a clue where an earlier 90 in lb number came from. That's above the max permissible toque value for any of the screw sizes I just noted.

10-31-2009, 11:18 PM	#9
plane Bad-ass Super Contributer! Join Date: Jan 2006 Location: Gilbert, AZ Posts: 773	Re: Prop Bolt Torque? Wow, have I gone through this exercise. I originally did the Garrett Morrison method of 37in lbs for wood and 40in lbs for carbon. The 37 works great for wood, but I found that 40in lbs for carbon was way to low. Those numbers were referenced to grade 8.8 bolts which is standard on 3W's. Those bolts can't take much more than 40in lbs. Later I read a thread about this and Jack Strickland chimed in that grade 12.9 bolts (used on DA's) can handle up to 70in lbs. After losing two carbon props, spinners, hubs I went to 12.9 bolts and torque them to 65in lbs. That finally solved all of my problems. The new DA170 is a whole new beast so be sure to torque them up to what DA recommends. My remarks are in reference to 150 class motors.

11-01-2009, 12:44 AM	#10
2walla Bad-ass Super Contributer! Join Date: Apr 2007 Location: Walla Walla Wa Posts: 1,162	Re: Prop Bolt Torque? Not the bolts you need to worry about- its the aluminum threads they engage in.. If you are actually looking at a table to pick the correct torque for the size bolts you use, you need to reduce it 30-50%. Thast why you see people using 40 in lb on a bolt that can handle 70 in lb... That is unless you like installing helicoils...

11-01-2009, 12:49 AM	#11
plane Bad-ass Super Contributer! Join Date: Jan 2006 Location: Gilbert, AZ Posts: 773	Re: Prop Bolt Torque? Helicoils suck...Timeserts my man. BTW, I have never had the aluminum hubs fail, it's always the bolts that break because they came loose from insufficient torque.

11-01-2009, 07:07 AM	#12
zzw26n Bad-ass Super Contributer! Join Date: Mar 2006 Location: Shelby Twp., MI, USA Posts: 1,855 Awards Showcase Total Awards: 2	Re: Prop Bolt Torque? Is the Torque rating in the DA Manual?

11-01-2009, 08:02 AM	#14
zzw26n Bad-ass Super Contributer! Join Date: Mar 2006 Location: Shelby Twp., MI, USA Posts: 1,855 Awards Showcase Total Awards: 2	Re: Prop Bolt Torque? Thanks John! may I ask where you got the info? I was going to copy it and save it as a Word.doc

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