|Aug 24, 2014, 08:34 PM|
I ordered a falcon 25x8w carbon to try out on the DA 70
Weights of my props
24B wood 126g
Falcon 24x9 carbon 153g (drilled for a DA70)
24x10 TH 175g
|Aug 24, 2014, 09:31 PM|
I bought a scale to put in my trailer and I lent it to Tyler to get data on the AW 60cc freestyle. I will get it back and do up all my props in my trailer one of these days. There are a LOT of them in 2 bins.
For my DA-35 I have the Vess 20B, Falcon and Mej 20x9s, as well as I could throw my Mej 21x8 or PT 21x10 at it once they are drilled. I have a 19x10 PJA drilled for the VVRC. I clocked the Yak at about 110 on GPS with it. To be honest I have been playing with MXS and my DA-120 stuff so much I have not touched any of these motors in weeks.
For the MXS got a good 7-8 flights on it today with the new ICE2 120HV on it. Finally got the CG where I want it with 3300s. The ESC is farther back and I put a "heavy" tail wheel on it. I was using V4.20 beta. Not sure if I should try 3.27. RPMs on the Falcon 23x9 were similar, if not better than the Gecko.
Xoar 22x10 was cavitating at low airspeeds. Sounded aweful.
Went back to Falcon 23x9. Flew most of the day with it on different battery combos. We stuck the GPS in it and it is around 95 mph on fresh packs. 7600 RPM on the ground. 7800ish in the air. Forgot to set the voltage alarm and had a LVC. flight times were between 6 and 4.5 minutes depending on batteries.
Tried Falcon 22x10 which was much better than the Xoar for some reason. This will probably become the standard prop, if not the 21x10.
Last flight was Xoar 22x8 which I bought for my other setups. Felt like it was stuck in 3rd gear, but man was it stable in low and slow. Felt very much like my 72 extra a 9.75 pounds.
The best it felt was when I flew with the 3300s as I had the CG correct. Only had 4.5 minutes with the 23x9, but with the 21x10, this would be a good combo with 13.6 or 7 AUW and get the flight time back up.
My next step is to get the CG better. I might be able to move the RX and stuff aft or just add a ounce or two of lead to the tail gear. I suppose I could put in heavy Savox 2231s or something like that and have stupid tail torque. The ideal thing would be to relocated the rudder servo, but that would take some engineering.
Everyone was wowed by the sheer power of the setup. Only DA-120 setups remotely feel the same to me. It equals the 60" 6S power, but at a much larger scale.
Another thing I did today was swap the 1.5" aileron arms for 1.75". I am maxing them out now. Got 56 down and 57.5 up. I have only used my 80 degree up rate once so far as I have set my mid rates to 60 and don't feel the need for the airbrakes. I like down elevator moves and that is maxed out by the horn.
My buddy got to fly his gas version back to back with mine and back again and I know he missed that stupid power. Says they fly close to the same in regards to lightness and trim, but his CG is better.
|Aug 24, 2014, 09:52 PM|
Check out this cool little device... Looks like mAh counting isn't far fetched for us castle/spektrum users. Will be interesting to see how it works.
Here is the manual:
Here it is in stock:
|Aug 24, 2014, 10:05 PM|
Yeah, really great stuff. 13.75 lbs is what I figured with the 2x 6S 3300's... my Sky Lipo 2-pack is between 1075g and 1084g depending on what batteries I put together. Anyway, nice to see the weight come in close to expectations, so thanks to Ryan and Matt for helping with that.
4.5 minutes is tough tho. With 3700's and the 21x10 Falcon, a possible 92 Amps peak could mean 5.5 minutes at 13.89 pounds, which is 25.3 WL and an 8.55 CL, which is right where most of my favorite setups come in.
The 71 Slick at 10.35 is 8.56 with a 23.0 WL, and your 72 330SC at 10.25 is 8.35 with a 22.5 WL. My 74 Edge at 10.88 now with bling added, is 8.30 with a 22.9 WL.
This may be worth assembling with a really light A60-8S with the 21x10 on 3300 12S for about 69A and 6.6 minutes just for the hell of it at 22.7 WL and a 7.87 CL. I can always go heavier.
|Aug 25, 2014, 12:46 AM|
I weighed the MXS including wheel pants and blind nut hdwr at 70g and another 14g (probably more like 3g) to fix where they were cut too big by the factory.
2x 2600mah Glacier 2s rx lipos
2x 7955 elev
Hanger 9 1-1/2" arm on ail, 2" on elev
SWB 3-1/2" arm rudder
21x8 CF Prop
Fortitude 12oz tank
DA Fuel dot
This bone dry never fueled 207oz (12.93lbs.) add 12oz. of gas 219oz (13.68lbs.)
Using half tank like above 13.31lbs
|Aug 25, 2014, 09:47 AM|
Thanks, Alan. Here is what I had using the 124.41 empty airframe component weights from Ryan, and engine weight from Enterprise7 (Matt) and others with the ES pipe, along with my components....
Empty out of the box = 124.41
Receiver = 1.20
Hard, Soft, Switches = 1.03
Kill Switch = 0.35
6 Savox SC-1268 Servos + hardware + extension = 17.83
2x 2S 2600mAh Fromeco Ign + Rx Batt = 6.60
Ultra IBEC = 0.60
CF Spinner = 1.52
23x8 Xoar = 3.90
DA35R + plug + prop hardware = 33.50
DA35R Ign Module = 5.26
DA-35 ES Pipe = 3.62
35cc Header = 3.69
Pipe Clamps + Couplers = 1.25
Alum 2.5 in Standoffs+ 8 bolts = 2.79
Total = 207.55 oz or 12.97 pounds
|Aug 25, 2014, 11:30 AM|
How light on the batteries would I need to go to to simulate the weight you are looking for on the 8S. To do 12s 2200 I would have to put 3 4s 2200s into series. I could do 10s 2700 zippy compact 35c.
|Aug 25, 2014, 11:50 AM|
Power Systems for Extreme Flight Fanatics!
I think 12s 2200 is small and would give you low flight time. I use 12s 2600s in my 10.3lb plane and fly between 6-7 mins. IMO, 6s 3300s would be about right for A60 and 4330 sized motors on a 12.5-13lb plane. 8s 5000 or 10s 4000 will give similar runtime and weigh about the same.
|Aug 25, 2014, 01:17 PM|
PJN 10-Pitch Issues
Matt sent over his flight data with the various props for review, and this is what I get from it…
First of all, the cavitation he was getting from the PJN 22x10 seems like the common issue we are having with the 10 pitch PJN props. For some reason, beyond my understanding at this point, the 21x10 and 22x10 Falcon props are not displaying the same issues. Since the prop is an airfoil, I think it is acceptable to call this a stall, although many will argue about it being technically the same physical phenomena.
I don’t have the weight of the 22x10 Falcon, but my 22x10 PJN is 87g and my 21x10 Falcon is 86g. I’m giving weights here because weight is part of the load formula that I use, and load is probably relevant to this issue. Not sure tho.
The in-flight data shows the motor is powering the 22x10 PJN to 285 more RPMs than the Falcon 22x10, and this can be part of the explanation because eventually, EVERY prop can be spun to an RPM where it will lose efficiency. If we speak about load in terms of the motor’s ability to spin one prop faster than another, it seems possible that the PJN is loading less than the Falcon, and spinning up beyond the efficiency limit. This is just my take on it, and may not explain the fact that the very same motor spun the 21x10 Falcon to over 7700 RPMs. It could be a design difference, or it could be that the diameter is also part of the efficiency curve value calculations. If so, I've added some tip speed numbers below as a comparison.
Either way, it may explain my subjective bias toward Falcon props. To be fair, I may also be trying to qualify that bias, and I have no other data to back up what I’m seeing here, or what I feel myself. Regardless, here are the objective in-flight data results. As always, these are not peak representations. They are values that are reproducible throughout most of the flight envelop:
Xoar 22x8 PJN
3.506v per cell
25.6 lbs calculated thrust
55.9 mph pitch speed
Falcon 22x10 E1
3.522v per cell
31.1 lbs calculated thrust
68.8 mph pitch speed
3.663v per cell
34.9 lbs calculated thrust
65.1 mph pitch speed
Xoar 22x10 PJN
3.673v per cell
If this prop was capable of delivering this RPM level cleanly, it would mean a 71.8 mph pitch speed.
Here is my data for the Falcon 21x10 E1, formatted the same way, but in static testing only:
Falcon 21x10 E1 Test 1 (no evidence of inefficiency/stall)
3.589v per cell
27.5 lbs calculated thrust
71.3 mph pitch speed
Falcon 21x10 E1 Test 2 (no evidence of inefficiency/stall)
3.666v per cell
29.1 lbs calculated thrust
72.8 mph pitch speed
Tip Speed: If this is not about load, or design, the other physical relationship between the 22x10 PJN and the other 10 pitch props is the tip speed. The 22x10 PJN tip speed is at least 20 mph faster than the other two 10-pitch Falcon prop, and close to 500 mph. I would have to look closer at the efficiency curves for these prop specs and see if there is a relationship to tip speed. If anyone knows about this, feel free to add your thoughts.
|Aug 25, 2014, 01:48 PM|
|Aug 25, 2014, 01:50 PM|
I was just trying to get the planes weight down to simulate the A60-8S 12s 3300 setup. Maybe do a video. I know it be will be a silly short flight.
My 45c 3300s are supposed to be 1120g. The 5335 is close to 400 grams heavier than the A60-8S so I would need the batteries around 720 grams. I think 12s 2200 will work out right. I have 3-4 4s 2200s that I could cobble together and run. I think my 5s 2700s would work as well, but I won't get the correct power.
My AJ laser will be a A60-8s on 3300s so I have this exact power system.
|Aug 25, 2014, 02:17 PM|
Sure... anything under 12.75 pounds with the tips on and the 21x10 to about 6800 RPMs should duplicate the 3300 setup, or 11.85 pounds with the tips off under the same power. 11.85 will bring it back to 250 Watts per pound that can be duplicated throughout most of the flight. I'm pretty sure I can do that with the A60-8S on 2x 6S 2600's and a little over 5 minutes for me to 20% capacity.
|Aug 25, 2014, 06:38 PM|
I just looked at the weight for the 4S 2200's that I had here and they were 221g, so 3x 4S 2200 would still be about 12.84 pounds. 11.85 pounds is going to be tough to match with that motor.
10S with the 23x9 Falcon on the DM5335 will equal the Watts of the A60-8S with the 21x10 on 12S with more torque, but the lightest 5S 2200's I've seen will still bring this thing in at 12.93 pounds. That's still under an 8.0 CL, but barely... 7.96.
So the 23x9 on 10S 2200 may give you a feel for a sub-8 CL at the top end to 2900W at 6370 RPMs, and the 21x10 Falcon should give you a feel for the mid-range at just over 2330W.
|Aug 26, 2014, 12:54 AM|
United States, MA, Lowell
Joined May 2004
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