Trex 700L TOP & 700xn don't feel the same

[chrisleematt21]

I have a Trex 700L TOP with a VX1n and a Trex 700xn with a VX1n.

Both were new, built by me, setup by me, and are setup as similar as possible (head speeds are different).
They are running very similar servos, I believe they are similar weights, but would need to check.

The 700xn flys a lot nicer, it always has, but i'm not entirely sure why!
Everything is easier, smoother and more precise than with the 700L.

Any ideas?

[Grumpy]

Headspeed makes a big difference it could be that the headspeed you have on the XN suits your style better. Try running the L at similar headspeed to the XN.

[chrisleematt21]

I'll give it a go, be nice if its that simple

[anjki]

My models have always been the same. A lighter feeling more precise on the nitro, even though both models E and N set up similar. I’ve been trying for years to get my 700e’s to fly like 700n’s...I can conclude it’s just not possible.��

[chrisleematt21]

My models have always been the same. A lighter feeling more precise on the nitro, even though both models E and N set up similar. I’ve been trying for years to get my 700e’s to fly like 700n’s...I can conclude it’s just not possible.��

That will be a tad disappointing as I Kin' hate nitros! (well when they go wrong )

I will play with the head speeds tonight and see what occurs, I did see a thread on heli freak and someone has both the 700l and the 700x and it was about 400g lighter (I think that makes it similar to the 70xn), could weight also be part of it? or doesn't it make much difference?

[trillian]

Weight will definitely make a difference, and also how the weight is distributed. The closer the mass is to the rotor disc and the main shaft, the less inertia it will exert when changing directions.

I assume you have the same blades on them?

That will be a tad disappointing as I Kin' hate nitros! (well when they go wrong )

I will play with the head speeds tonight and see what occurs, I did see a thread on heli freak and someone has both the 700l and the 700x and it was about 400g lighter (I think that makes it similar to the 70xn), could weight also be part of it? or doesn't it make much difference?

[chrisleematt21]

Weight will definitely make a difference, and also how the weight is distributed. The closer the mass is to the rotor disc and the main shaft, the less inertia it will exert when changing directions.

I assume you have the same blades on them?

Yeah, both are using the align 700mm blades.

[trillian]

Does the L have those angled grip arms like the XN ? I really wouldn't think that alone would make a big difference but it could change the geometry a bit.

[Grumpy]

Does the L have those angled grip arms like the XN ? I really wouldn't think that alone would make a big difference but it could change the geometry a bit.

I've run both the standard and the angled grip arms on my 700X and I can detect no difference in flight. The angled one do work in removing differential in + and - collective travel, but with the stock arms that can be dialled out in FBL setup anyway.

[waveydavey]

Chris, I can vouch for exactly what Andy says above. I've watched Andy fly at the club and in comps and he has always flown N's better than E's. The head unloads differently so it appears smoother, it's a little heavier to start with and gets lighter as it goes on, the power is more progressive so you find yourself flying differently and nursing the engine on feel rather than endless punch. I'll also add that Duncan flys an N better than he does an E. Of course only the opinion of a ham fisted Geordie

The closest Andy got an N looking like an E was a Logo 600 and the famous/infamous Kylie flight at the 3D Champs

[anjki]

Chris
If you prefer the way the nitros feel, I’ve found reducing both weight and head speed on the E’s will help.
Disk Loading comes down and on a calm day I feel they are unbeatable, dare I say as nice as a nitro 700 to fly!
The problem is when it’s windy the lighter weight E become’s hard work and very inaccurate to fly.
This is when the standard 5kg plus 700e comes into its own. I’ve now learnt to enjoy the light weight E‘s when calm and fly a more out the box type 700 with 5000mah plus packs when it’s any more than calm.
I enjoyed the nitro and the tuning/tinkering for years but it’s just not what I want any more, so I’m learning to live with the compromise.

[Rachel]

you cant change physics ! a nitro will always feel lighter than an electric,... its about disc loading , inertia and the power units are totally different in the way they both accept load and recover from it !...... I gave up flying nitro as I compete,... its too susceptible to atmospheric change, and can be unreliable,.....enjoy them For their differences xxxx

[Grumpy]

I've never owned a 700 nitro.. So for the average 700 nitro what would a typical fuelled flying weight be?

A 700 electric can be build under 5Kg, so is weight really a fundamental and unavoidable difference? I'd be surprised if an average 700 nitro is very significantly lighter than a 700 electric that's been built with an eye on weight.

[trillian]

Electric helis can be setup way lighter than nitro because you have so much potential to vary the pack size. So the subjective feel has more to do with the power delivery.

I've never owned a 700 nitro.. So for the average 700 nitro what would a typical fuelled flying weight be?

A 700 electric can be build under 5Kg, so is weight really a fundamental and unavoidable difference? I'd be surprised if an average 700 nitro is very significantly lighter than a 700 electric that's been built with an eye on weight.

[hedge]

An interesting view on the above

http://www.rcheliaddict.co.uk/main-d...ngly-good.html

I think when most of us think 700e we think of comps/tareq esq flyers so 2x5000mah high C rated probably opti batteries. of course there are people who run single 6s or twin 2800s but "normal" is 2x5000 ish batts.

It does not seem like it should be impossible to get an "e" to fly exactly like an "n" (the other way around would be challenging as N does not have the horses "E" does) unless the delivery of power is the difference - clutch/gov vs e-gov?