Originally Posted by horsefeet

in edf why does good or better always have to cost the most...

EDF fans and motor setups only, IMHO ,has the prices graduated pretty decent relative to thrust for adequate then good then best for the price.

For instance, for best 90 mm the fan\motor combo should be able to handle a 13 - 15 lbs of thrust time and time again at different cell counts and cost 250 dollars

For a 90 mm fan\motor that does 8-11 lbs the costs are around 150 and around 90 - 120 usd for lower thrust performance depending on the thrust tube shape etc

it is electronics shouldnt they be able to produce same a lower cost and we can all share in great performance at a fair price.

This is another area were EDF has the prices decently graduated from 6s to 14s esc's

The cool thing about the K-30 IMHO is it will get more gas turbines at fields since the cost of the motor is now less than the cost of a 30 - 40 lbs turbines.

In that link the guy makes his own pipe out of a long aerosol can..

Originally Posted by pmanning

Inside view of Scorpion (our LHS won't let us pull the edf unit out of the NIB to get a really good look).

It looks like the 800cc tank will fit with a little more foam removal on the inner 'y' sides. Do you think removing the foam connection between top and bottom weakens the wing tube area too much (to the point of needing a former around the fuse interior, and/or just around the tank)?

I couldn't help myself and added a small fiberglass patch over the bottom 'y' area. I have nightmare's that the tank will come bursting through the belly when pulling up on the elevator.

Thanks,
Paul

The stock power setup in the fms 90mm is super light, that is what I fitted to my Hobbyking Skysword as the fan was only 330 grams with motor.

Skysword is another option for me to tubinate with a k30, plenty room to suspend the turbine way forward from the stock location (will need thrust tube) , could prob cut the intake ducts from the inside to hold a tank over CG and loooong nose to aid balanceing the plane. Stock Skysword flys really light at 3600g , even if it weighed over 4 kg wet at take off I am sure it would quickly come down in weight and land lighter than my 6s 5000mah setup. Would be a proper challenge to see if it can be done with no lead added.

I found out that although the K30 can theoretically run with diesel due to the tolerances of the micro pump it is not recommended as its near impossible to finally tune the start procedure without the chance of a wet start.

Originally Posted by erh7771

Nice pics of the inside

How much do you think the ESC weighs?

3 oz?

Thx in advance

I estimate that by itself, the esc is 160g (Predator 130amp). It has a large aluminum heat sink, 10 ga wire, 3 capacitors, and small bec.
The fan/motor are approx. 350g (plastic housing).
Unfortunately, 505g includes everything that's coming out, including the esc (hidden under the fan unit on the scale).

Skysword with p20 pushed right back and still managed CG, plenty performance as well.

https://www.youtube.com/watch?time_c...&v=kUL2inj5NkY

I need to fly my edf version more and see how far back I can push the CG, then see if its possible with 450g in the tail and no 6s 5000 lipo fitted lol. Rather not have to fit a thrust tube if not needed.

Originally Posted by pmanning

Inside view of Scorpion (our LHS won't let us pull the edf unit out of the NIB to get a really good look).

It looks like the 800cc tank will fit with a little more foam removal on the inner 'y' sides. Do you think removing the foam connection between top and bottom weakens the wing tube area too much (to the point of needing a former around the fuse interior, and/or just around the tank)?

I couldn't help myself and added a small fiberglass patch over the bottom 'y' area. I have nightmare's that the tank will come bursting through the belly when pulling up on the elevator.

Thanks,
Paul

I would first try to fit the tank where your dubro is located. In the same direction, if that not work I would put it on it's side, shave foam to make the floor level with the wing spar tube. Then cut "y" as far forward as needed. In this way the tank would maybe block some of the ducting looking from the intakes, but that does not matter.

Carve a 800cc tank in foam or 3D print a dummy to se if it fits.

Originally Posted by raydar

Skysword with p20 pushed right back and still managed CG, plenty performance as well.

https://www.youtube.com/watch?time_c...&v=kUL2inj5NkY

I need to fly my edf version more and see how far back I can push the CG, then see if its possible with 450g in the tail and no 6s 5000 lipo fitted lol. Rather not have to fit a thrust tube if not needed.

With a nose that long, how could it not work? I passed on the 70mm version so far though as I could not see a clear patch to getting the fuel at CG. The P20 video shows the fuel pretty far forward. Simply not my thing. If I can not get the fuel 100% at CG I will pass on the build.

Which made my little A6 a true challenge, there is an engine where the fuel needs to be...

Originally Posted by raydar

I found out that although the K30 can theoretically run with diesel due to the tolerances of the micro pump it is not recommended as its near impossible to finally tune the start procedure without the chance of a wet start.

This is a big thing to Lambert success. He makes his own pumps for each engine size with the right gears in them.

I think they will run just fine on diesel, you just need to figure out which blend of diesel you have and go from there.

We got 7% oil in the diesel stright from the pump here, ready 2 go Jetfuel

Originally Posted by henke

With a nose that long, how could it not work? I passed on the 70mm version so far though as I could not see a clear patch to getting the fuel at CG. The P20 video shows the fuel pretty far forward. Simply not my thing. If I can not get the fuel 100% at CG I will pass on the build.

Point taken henke no arguments here however if I am willing to compromise a bit to use what's at hand I may be able to reach a compromise using a header tank and thinking cleverly.

By no means set on this airframe yet BTW, hopefully get some weights off pmanning when his turbine comes and mock up how much weight would be required on the nose,
think it will be very difficult to balance with k30 and no thrust tube .

Where people often fail is that they won't extend their cables to the turbine putting the stuff where the EDF Li-po used to sit.

I would do it this way, and hopefully it would go well..... with a ruler and some calculations you could easily se how it will turn out. I don't have time for that at the moment, will do it later.

That look good, the motor can be moved forward a little, custom pipe either way....

Wow nice work henke, cheers. Stock edf in mine is 330g and esc another 130g, a very light setup. There is a big question mark over CG in this plane though as I fly it at 140mm and know its nose heavy at that!!!. 70mm version has proven to fly well at 140mm so hoping the 90mm version ends up nearer 150mm to 160mm which of course is a huge difference.

I def would extend the turbine wires if/as required and bury the 3s lipo in the nose cone, hoping that if I can get to within 3" of tail pipe not need a thrust tube???. Dancy a thrust tube is not always required, henke has proven that though a small tube might be easier for GC, install and accessibility.

My k30 is ordered BTW, may not end up in a Skysword yet, but fingers crossed.

Originally Posted by Dansy

That look good, the motor can be moved forward a little, custom pipe either way....

Yes, but if not needed, actually better having the flame thrower out the back.... A tube with mounts adds maybe 3oz, long or short.

Now let's do it. The units we use are not so important as long as we keep it the same. So mm and grams it is.

_____________________________________

Battery = 220mm*850grams= 187000

Turbine accessories = 187000/700 = 267grams to counter the missing 6S Lipo
____________________________

EDF + ESC = 108900+ 16900 = 125800

Turbine engine = 125800/440mm = 286 grams allowed.

__________________________________________________ ___

Lucky saturday for me as these numbers are extremly close to how a Kolibri T35 Setup would look haha

For the kingtech we add 164grams*440mm =72160 in the tail.

Counter in the nose 72160/700 = 103grams

__________________________________________________ ___

So for the K30 setup the nose weight need to be 103+267 = 370grams

In this case it would actually make good sense mounting the engine well in the tail to avoid a potential BBQ party.

Doing it this way is so useful and you can do it so good without even having the airplane. If the counterweight needed is many pounds, then just don't do it. For a Venom/Vampire missing the long nose, we would be up 2lb easy!!

Has kolibri mentioned anything about the kero start or new ecu they are testing? Anything new regarding their current t35?

Finally, a class worth moving into the front row..

Not ready to hand in my homework (schematic) but so for the Scorpion,
1) Moving the K30 100mm forward reduces the required nose weight by 219g (even though it is only 55 grams lighter in total weight than the edf/esc components it replaces).
2) Removing the Battery adds 393g to the nose (based on average component location - lots of room to spread things out)
3) 174g net required nose weight (393 - 219)

I'll need to calculate a bit more for each forward component weight/location but the bottom line is the pilot can stay. Should be no need to hollow out the forward canopy to stack stuff up in the nose.

Thanks (Prof.) Henke for explaining the math... I won't say the 'light' came on but it's not as dim as when I started.
Paul