S800 alternative props

atomkind

Member

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nisouck

Member
If that shaft had had a 4 mm hole through the middle it would have snapped off in half the time while you were in the air.

That's definitly the problem.
To avoid it, 2 solutions:

1° Make a plate thicker.
2° Cut the shaft and reduce the length of middle hole.
 

DennyR

Active Member
I do not know the correct torque as i do not have a meter for it.

I simply tighten them till the props stop slipping.

I use steel nuts on them and it does not feel like the nut picked the thread. I just destroyed the thread with vey less force, before the prop stopped slipping.

I will meet a friend who works as a material engineer for a metal manufacturer to show him the parts. I think this is not a problem of 1 in 200 but the wrong material for this use. Do you have the specific code for the alloy material you use?

I think non corrosive steel would be the way to go for the adapters.

So everybody who makes adapters has got it wrong then! for years now they have all used Alum. All the motor manufacturers etc.etc.

60/61 is the type of material that is used (I don't know how many times I have to say that before it sinks in) and there is only one aircraft grade higher. 6mm thread is universal and one person has a problem. You have over-tightened the nut at some point. If that were not the case then everybody would have the same problem.

If I did not know better I would say that someone put you up for this. I'll make them from titanium if you can afford them.
 
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DennyR

Active Member
That's definitly the problem.
To avoid it, 2 solutions:

1° Make a plate thicker.
2° Cut the shaft and reduce the length of middle hole.

That is not the problem because the 4mm hole on my adapters does not extend into the shaft. That is someone elses problem
 

mitmit

Member
With a S800 and 15x5 Xoars and a 1100 maxamps you should be getting at least twenty mins
Hey Denny,
I have couple of very similar to s800 hexas. have tested about 10 different props from apc14 to some xoars and carbon 16's and was never able to get 20min with about 1,5kg payload (6kg AUW). 15-16min max with 6s 10Ah. thats why i'm asking for a proof, 22 min looks just impossible to me.
 

atomkind

Member
Hey Denny,

No offense here! Maybe I am to dumb but I can´t tighten the adapters often without weakening the material to fail.

After talking to a colleague he sees two issues on them. He thinks that there is a possibility for alloy threads to hold the torque when the torque is not cut but pressed and the alloy is eloxated to harden the surface. I need a lot of torque to tighten the nut enough and avoid slipping on the xoar props. My adapters failed after several prop changes. Maybe I got an older version with a not as good material?

Another issue he mentioned is possible corrosion than might happen when alloy meets a steel nut. (maybe in long terms)

Nevertheless, we will have prototypes by tomorrow evening made of 1.4112 steel that will hold the necessary torque easily. Of course they will be heavier.

I will send my adapters back to my retailer then as I think that they are simple to weak for the torque that needs to be applied.

Please do not get this wrong! This is not an offense!
 

DennyR

Active Member
Hey Denny,
I have couple of very similar to s800 hexas. have tested about 10 different props from apc14 to some xoars and carbon 16's and was never able to get 20min with about 1,5kg payload (6kg AUW). 15-16min max with 6s 10Ah. thats why i'm asking for a proof, 22 min looks just impossible to me.
The endurance is affected by temperature quite significantly and also the state of the Lipo. I was getting over 20 mins in the hot summer 35-40 deg. and taking the discharge to max. limit with new batteries. The Maxamp 11,000 ma. battery is quite different to others that I have tried. That model is now living in Moscow so I will ask what is happening there. I am not sure what the ESC spec was from DJI but the motors and the ESC's were barely warm afterwards.
If you want to fly for one hour then you need one of these.View attachment 8026 it has two maxamps 11 amps. 45V. and very efficient blades. 700/45 Pyro motor. About to try it with a Naza-H.
It is based on a Henseleit which holds a world record of just over 260 KPH. It is a pretty good energy converter. This one uses only 900 rpm head speed and can still fly inverted. At some point in the future I will try the Goblin 770 and 14s batteries.

I'm sure I don't need to explain to you how to prepare and look after Lipos but it goes without saying that proper storage, balancing and an accurate check on internal resistance is the key to getting the right efficiency from them.
 

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mitmit

Member
The endurance is affected by temperature quite significantly and also the state of the Lipo. I was getting over 20 mins in the hot summer 35-40 deg. and taking the discharge to max. limit with new batteries. The Maxamp 11,000 ma.

yep i know it) all batts were 5-6Mohm IR and i put back about 9Ah.
all in all, the average endurance of s800 with standard auw about 6-6.5kg seems to be about 13-14 minutes. the only over 20min results I ever heard of are yours and Sandor's actually.
probably this is that famous maxamps magic, i did not try them so any proof links to 20min fully loaded s800 flights are highly appreciated.
ET recorder is very useful for that kind of tasks btw. here is testflight of 7.1kg hex with 16x4 Xoars, 2x4Ah batts and 400kv motors for example:
View attachment 8027

as for heli endurance - agree, i'm about to revive my Mjokers and give them another try) what asymmetric blades do you use on Henseleit btw?
 

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Digitech

Member
i dont use max amps anymore , they may still work on s800.
but on our cinestar they just collapse.
the True 45C as they claim is infact only 5C , the 45C is for a short burst only.
i stopped selling them.
if anyone wants a bunch of 5S 11000 i want to part with them they are 50% of the price that max amps is asking , but need to take aminimum of 3 pieces.

the 22 minutes is flown with a Gens ace 10000mah 6S.
i dont see a need to prove myself.
overhere and germany you only sell what is true , otherwise we get burried under "product Haftung"
 

Digitech

Member
even axi adapators break if you apply anough force on them , sorry i am with denny on this one.
if you apply normal force , all will be ok.
remember this is not a petrol engine , most of those have a lot of vibration and torque.
if you decide to use steel , your bearings will suffer the ultimate gyro problems theye have.
the higher you go , the more problems you will have.
we still use flat props , without adaptors , instead we use reinforced carbon booms for the s800
 


ChrisViperM

Active Member
I also use prop adapters from Denny, and similar ones from Tiger Motors (got them from Digitech). I had both of the adapters and changed props for test reasons countless times....and both adaptors look like new. Anyone with a little material knowledge knows that aluminium (adaptors) and steel (nuts to tighten the prop) are just "poison" in the real world, and in industrial application everyone tries to stay away from this combination. BUT.....it is possible - if necessary, and especially in case of the adaptors.
Making them from steel/stainless steel would create so much rotating mass that your motor bearings would just disintegrate, unless you balance them with special equipment which is pricewise comperable to buying adapters made of gold.

To make the adapters long-living, someone has to take care for a few things....ALWAYS make sure that the threads of the adaptors and the nuts are totally free of any dirt, particles or just anything which doesn't belong there. Check the treads with a magnifiying glass for any signs of wear.
Fit the nut onto the adaptor as far as you can (at least a couple of rotations) by hand - that way you would feel if there is something on the thread which doesn't belong there, you also feel if the nut is "sitting" properly on the adaptor thread or not. Also check if the end of the adaptor thread is "deep" enough in the mounting hole of the prop, once tightened the nuts should still be away from the end of the adaptor thread a few rotations. Once you tighten the nut with a tool, you actually don't need a torque wrench, just use common sense - the nut just needs to be tight enough to hold the prop in a way that you can't move the prop by hand with "a lttle bit" of force while holding the motor....if you follow this, you don't have stripped threads.

Anyone thinking this is too much efford for "stupid" prop adaptors....might be a sign of being in the wrong hobby/profession. I am the most chaotic person on earth (ask my wife) but when it comes to Multirotors, I am more than paranoid about EVERY aspect that keeps the bird in the sky, maybe this is one reason why I did not have a single crash after countless flights with Singlerotor helis and Multirotors.

Chris
 
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atomkind

Member
Chris,

I could not tighten the nuts hard enough to avoid prop slipping (when you hold the motor and try to turn the prop) Are you sure the props are allowed to slip? I simply do not want that to happen during flight.

I seem to be the only person with this issue. Ok. I never had this problem on other prop adapters (from cinestar or mikrocopter) so I am wondering why this happends with Dennys adapters. Maybe I got a different pre release material version? The alloy material on mine seems to be very weak, just like the stuff you get at the hardware store.

Titanium would be another alternative or maybe eloxated and properly threaded alloy. Titanium adapters wouldn´t be too expansive.
 

ChrisViperM

Active Member
The props should not slip at all.....
- the nut just needs to be tight enough to hold the prop in a way that you can't move the prop by hand with "a lttle bit" of force while holding the motor

If you say you cannot tighten the nuts hard enough to avoid prop slipping, then there is something wrong. Maybe your prop is too thin (the nut reaches already the end of of the adapter thread before producing enough force to hold the prop in place) Sometimes, especially if the unthreaded part of the prop adapter is too long or the surfaces of the prop is very "slippery" and cannot produce enough friction, it might be useful to use any kind of locking washer:

http://www.google.at/search?q=locki...aDMbKtAaz4oDoCg&ved=0CDEQsAQ&biw=1760&bih=854

But always on top of the prop and never on the bottom side.....if the prop adapter becomes a little short because of the washer, simply apply a very small ammount of blue thread locker.

Chris
 



cs8

Member
I have a set of Denny's prop adapters and Graupner 14" props for sale. Flown 3 battery packs.
PM if interested.
 

Eoin

Member
Hi Guys,
Finally got around to trying Denny's adaptors today with the APC's. Build quality is spot on and I didn't find any issues putting them on.
The S800 flew beautifully ! It was a pleasure to feel how smooth and responsive it was. Also much quieter. Don't think I'll be going back to the stock props. Probably going to order a few more from you Denny, as backup.
Also going to order the Xoars. If the reports on the Xoars are true and they are smoother than the APC's I'm really looking forward to them.
 

mitmit

Member
Also going to order the Xoars. If the reports on the Xoars are true and they are smoother than the APC's I'm really looking forward to them.

in terms of flight feelings (not vibration): apc's are the most smooth props. with xoars you will have much more nervous response.
 


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