Logo 700 Xxtreme Stretch

[DT Blade]

Hello all,
I have a an Xxtreme 700 that I am just finishing up. I am wondering if there is anyone that has stretched one out with 770mm main blades and the 800 boom/struts of course. I am really interested in what the max headspeeds that would be safe to run? I would like to get up to 1900. Thanks for the input.

[taosgraveyard]

The booms are different lengths it's true

But the frame of the 800 is longer than the 700 so the question is the belt... If the front belt pulley isn't in the same position in the frame on the 700 as it is in the 800, the 800 belt won't fit

I don't have my 800 with me in Argentina, it's still in the USA, or I would measure for you,,,

I don't remember anyone doing this stretch, hopefully someone will chime in,

Also, in my 700 I had trouble when I went to 14S... Had to use 4400 mah 7s battery, and that is mounted as far rear as it will go. Anything larger and the Heli would not balance, A 700 stretch could come out very tail heavy, using a lighter ESC would help... I am using a kosmic 160 on my 700.

[DT Blade]

Thank you for the info. I am hoping to use the 700 gearing, is there a reason for using the 800 gearing? With a 17 tooth pinion at 400Kv running 14s will bring the HS down into a proper range for a 770. But i did not think about the CG. I assume you meant it will be very nose heavy, as you said tail heavy? Were you able to balance it with 716mm mains running 14s?

[rcmarty]

I have both and the gearing ( maingear/belt ) aret he same for the 700 and 800.

The frame set is smaller on the 700 in overall size.

The head of the 700 is a bit smaller in size than the 800. IMO there over sized (typical Mikado ) and should handle larger blades.

By comparison the goblin 770 swings 770 blades on the same spindle , no provisions for larger spindle/bolts for the stretch to 813's.

It's been done though

https://www.helifreak.com/showthread...hlight=stretch

Myself I'd like the lower profile for aesthetics purposes as the flying characteristics I don't think are going to be all that different.

Getting a kosmic cool 200 under the lid of a 700 canopy might be the hardest part of a 7-800 conversion. It can be done but it's TIGHT !

MArtin

[rcmarty]

..

[taosgraveyard]

Originally Posted by DT Blade

Thank you for the info. I am hoping to use the 700 gearing, is there a reason for using the 800 gearing? With a 17 tooth pinion at 400Kv running 14s will bring the HS down into a proper range for a 770. But i did not think about the CG. I assume you meant it will be very nose heavy, as you said tail heavy? Were you able to balance it with 716mm mains running 14s?

Yes the 700 came out balanced properly with 14S using the 7s gens a e 4400 packs, but with them absolutely as far back as they could go in the mount, and still be able to get them in and oiut of the frame. I am using a kosmic 160 with isn't light... A lighter ESC isn't necessary with that pack.

Thinking more about the 700 stretch:

The boom is longer on the 800, and the frame is lighter, so it would probably tend toward being tail heavy when usied with 700 frame... The frame is a white a bit bigger on the 800, and it balances with a 14s pack. Moving the rather heavy ( as compared to say, a 600 SX) tail box and rotor farthe back on the 800 boom, a 700 stretch Might still balance since there is a bit of room to move the pack forward.

In my 700, the kosmic ( not a cool kosmic) barely fits, I used a diabolo kosmic mount mount and flattened the curve of the front of the frame to get it to clear. I posted the modification in this forum.

Mine is so tight, I don't think I could get a kosmic cool in there... But I guess some have been able to,