RE: Nitro Planes A-10 Warthog for 95 dollars

RE: Nitro Planes A-10 Warthog for 95 dollars
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RE: Nitro Planes A-10 Warthog for 95 dollars - 4/1/2008 5:41:34 AM

websterphreaky

Posts: 78
Joined: 2/17/2008
From: San Juan Capistrano, CA, USA
Status: offline

RysiuM,

Great recap of the disassembly, making the "special" tools and fighting you way through the process. Also great research on what will and will not fit.

The disassembly sounds like it will be a nightmare. Did you have to break anything to get it a part? How did you keep from breaking the DF nacelle (pod) from breaking off the fuselage while fighting with the rotor??

I think that my son and I will try removing the motors first before investing in replacements. If we get one set off one of the two A-10s we have, then we'll buy investigate which upgrade components to go with. Otherwise, we'll just live with the limited flight capabilities and think about building a balsa based brushless electric from a kit, maybe a small glow engine DF. I already fly a single engine .46 glow DF A-4 Skyhawk we built a few years ago. Anyway, I can't see putting a lot of time and money into a $95 Foamy that's pretty brittle.

Thanks for the recap, well done!

(in reply to RysiuM)

Post #: 76

RE: Nitro Planes A-10 Warthog for 95 dollars - 4/1/2008 8:00:15 AM

RysiuM

Posts: 1297
Joined: 4/22/2003
From: Elk Grove, CA, USA
Status: offline

quote:

ORIGINAL: websterphreaky
The disassembly sounds like it will be a nightmare. Did you have to break anything to get it a part? How did you keep from breaking the DF nacelle (pod) from breaking off the fuselage while fighting with the rotor??

For easy handling remove everything that is not necessary. Remove the wing and the horizontal stab. Of course remove the battery too. This way the fuselage will be light so you can pick it up by nacelle without breaking them off by the weight of the fuse.

Next lay down the fuselage (I used soft sofa) and working around the rotor do not grab by the fuselage nor by the nacelle. The big mistake would be holding the nacelle or fuselage with the one hand while working on the rotor with the other. If you push only internal parts against each other you may move the fuselage accidentally, but if you don't hold it it will move freely. Right tool is the most important thing. Like I wrote, when I made my tool and I verified it works it took a minute to disassemble the unit.

Now I'm mounting new units in the plane. This is not as easy as removing the old unit. I noticed one tab with the hole for screw was cracked. I used odorless (foam friendly) CA and nylon cloth to laminate it. Then the next task was to fit the motor's wires. They are short and quite stiff. After I assembled one unit I found than my home-made set screws may hit the mounting screws. I need to buy the real set screws that will hide inside the shaft adapter.

Finally before I tested the unit I changed timing on the ESC to 30 degrees (the highest value). The unit gain some rpm (2-3k more) on 2s Lipo. It still may be a chance for flying on 2s 2500mAh battery pack. But I will know that after I finish both units and measure the static thrust.

Edit: One note about the motor. After testing my setup I know, tat I should have bought this motor with kigher kv for running on 2s LiPo. In example HXT 2435 (370S) 4400kv would be better choice for my setup. 10% more rpm would put me in the range of 25k rpm and 12A (I guess).

< Message edited by RysiuM -- 4/1/2008 5:17:23 PM >

_____________________________

Mather Aerospace Modelers, Inc.
AMA Gold Leader Club, Charter #1243, Sacramento, CA

(in reply to websterphreaky)

Post #: 77

RE: Nitro Planes A-10 Warthog for 95 dollars - 4/6/2008 8:01:18 AM

RysiuM

Posts: 1297
Joined: 4/22/2003
From: Elk Grove, CA, USA
Status: offline

I just finished mounting new motors. So here is the information that may be useful fore someone.

I programmed ESC with the following parameters (these are TowerPro N20A-S Acro):

002 - Airplane
1__ - N/A
200 - Brake Off
330 - timing 30 degrees
402 - Motor frequency 32KHz
502 - motor acceleration hard
600 - Battery LiPo
701 - 2 cells
805 - 2.5V cut off
900 - Motor Cut-off by slow down
A01 - 0% throttle pulse = 1ms
B04 - 100% throttle pulse = 2ms
C01 - Throttle curve linear
D00 - Left rotation
E00 - Timing motor ON.

At full throttle powered by Duralite 2s1p 2500mAh units (both together) take 20A producing 10-12oz static thrust
At full throttle powered by ThunderPower 3s1p 1800mAh units take 29A producing 18-20 oz static thrust. However at this setup rotors started to hit the unit (I noticed marks on the plastic).

I have setup the radio so left motor is controlled by channel 3 and right motor is controlled by channel 6. I mixed both channels making sure that the signal is exactly the same on on both channels entire range. A also mixed engines to ruder. The plane does not have ruder (only steering nose wheel) so I will see if asymmetric thrust will work as ruder. The mixing was done by adding power only. I used 5-point curve available in mixers 6 and 7 on my Futaba 8US. The radio has following setup for engines:

1. Throttle (Ch 3) and Flaps (Ch 6) are reversed
2. ATV on CH3 and CH6 are 136 (low) and 136(high)
3. Mix 1 Flap->Flap: -100 (low) -100 (high) Link off, Offset=+72. This mixer disables the flap knob and setts the signal on Ch6 equal the Ch3 at the lowest throttle stick position
4. Mix 2 Thr->Flap; +100 (low) +100 (high) Link off, Trim off Offset=1. This mixer links channel 6 with throttle stick.
5. Mix 6 Rud -> Thr: Pos1=0, Pos2=0, Pos3=0, Pos4=10, Pos5=20. This mixer adds power to the left motor if I move the ruder stick to the right.
6. Mix 7 Rud -> Flap: Pos1=20, Pos2=10, Pos3=0, Pos4=0, Pos5=0. This mixer adds power to the right motor if I move the ruder stick to the right.

I understand that at WOT the ruder will not have any effect on motors - it will work from idle to 80% power. This is because if I slam WOT that means I need full power, and I don't want to slow down any engine by ruder input. I will see how it works in the real life.

I will try to fly on 2s first and see if this works OK. May not. But this battery in the nose is balancing the plane very well. 3s makes the plane nose heavy. I'm not sure how I am going to solve that. It may require to move the nose gear servo all the way to the nose and use the space just behind the nose wheel for 3s battery.

< Message edited by RysiuM -- 4/6/2008 8:04:36 AM >

_____________________________

Mather Aerospace Modelers, Inc.
AMA Gold Leader Club, Charter #1243, Sacramento, CA

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Post #: 78

RE: Nitro Planes A-10 Warthog for 95 dollars - 4/8/2008 12:38:01 AM

websterphreaky

Posts: 78
Joined: 2/17/2008
From: San Juan Capistrano, CA, USA
Status: offline

Whoa, if the 3s1p 1800mAh units are making the rotors spin that fast to expand and hit the DF housing, you better hope the 2 cell LiPo batts work! Sounds like you've got a rocket ship there.

Thanks for the details on the set up and also deconstruction hints for getting the old motors out. Think we'll take a whack at modding one of the two Guanli A-10s my son and I have. Speaking of Guanli, my youngest flew the FW-190 I referenced in a previous posting for the first time. Despite never being able to get the horizontal stabilizer and the wing to line up on the same plane (pun intended) as it the styro casting area of the fuselage for the wing that is crooked; it flies decently and has adequate power from the 370 size brushed motor on a 1:5.3 gear system. It can easily do rolls, loops after a running start, climb vertical a few seconds, but inverts are tough to control. The motor is noisy as hell. This plane would really benefit from going brushless and LiPo batts, and would be very easy to do.

Good idea on using the two EDF's for rudder control. An old friend from the service who flew as first office for AirCal and then AA told me that the pilots who flew DC-9's and MD-80's were taught how to use the two engines if they ever lost rudder control (which happened on a couple DC-9's). I never like Douglas planes.

(in reply to RysiuM)

Post #: 79

RE: Nitro Planes A-10 Warthog for 95 dollars - 4/8/2008 3:59:01 AM

RysiuM

Posts: 1297
Joined: 4/22/2003
From: Elk Grove, CA, USA
Status: offline

quote:

ORIGINAL: websterphreaky

are making the rotors spin that fast to expand and hit the DF housing

I think I need to take it back. I noticed that at some speed rotors are rezonating with some vibration on the shaft. My adapters are not as precise as they shoud be. I mean I have made them with accuracy to 0.01mm but somehow they don't work well like the original GWS EDF Rotor. I'm going to make a couple more adapters and if this doesn't work I will start looking for GWS rotors.

_____________________________

Mather Aerospace Modelers, Inc.
AMA Gold Leader Club, Charter #1243, Sacramento, CA

(in reply to websterphreaky)

Post #: 80

RE: Nitro Planes A-10 Warthog for 95 dollars - 4/8/2008 3:32:47 PM

cyclops2

Posts: 1810
Joined: 12/23/2005
From: Frenchtown, NJ, USA
Status: offline

Warning!
I run the GWS EDF 40 impellors on the high side of 2 Hyperion 5800 KV motors. 13 vdc to start with at take off.
I buy just the rotors and drill a small hole thru the mounting hole to let the Lock-Tite oozz out if needed when pressing them on the shafts. None of the impellors ever were out of balance.
As I wind up the motor the noise is actually less at the very last 10 % of the WOT. Beyond my hearing range probably.
The blast area behind it is serious for such a tiny fan & motor.

(in reply to RysiuM)

Post #: 81

RE: Nitro Planes A-10 Warthog for 95 dollars - 4/11/2008 9:35:03 PM

RysiuM

Posts: 1297
Joined: 4/22/2003
From: Elk Grove, CA, USA
Status: offline

I finally made the adapter that runs smooth. I trimmed both engines so they run the same rpm. Of course it is impossible to have it in the entire range but close enough.

I took the plane for the test flight this morning. Very light wind, smooth air. I prepared two battery packs for testing. 2s 2500mAh Duralite and 3s 2100mAh Thunder Power. With the first pack the plane was a little tail heavy but I decided to try it like that. If the plane is underpowered I would try 3s that balances the plane a little nose heavy.

O had a long paved runway available so I decided to take time for ground roll before initiate rotation. When i rotated the plane jumped into the air showing it's tail heavy characteristic. It was tail heavy but controllable. The power from 2s was very good. Of course it was not a 3D plane but the flying was very easy on the power available. So I decided to back off to about 80 throttle. Engines smoothed out running at exactly the same speed. The plane still was flying stable. I tried how differential power works on turns but did not notice much difference. I did not use much "ruder" as I was afraid to put the plane into the flat spin, that with such tail-heavy balancing may not be recoverable.

After few lazy laps I decided to land. Landing was hot and shaky - model was very sensitive on elevator. On touch down model hit pavement hard, lost left landing gear and bounced in the air. I flew it for a couple seconds more loosing speed and finally it landed on two wheels. Just before stopping it dropped the wing where the landing gear was missing. It did not do any damage to the wing.

The landing gear mount popped out from the wing - I could see that Guanli did not use much glue there. It is easy to fix as the foam is not broken.

Conclusion: 2s fly this setup very well. Because I put both speed controllers on the back (behind the wing) the balancing changed. I can try use heavier battery (will be longer flight) or try my 3s pack. It will be interesting to see how this model flies way overpowered.

_____________________________

Mather Aerospace Modelers, Inc.
AMA Gold Leader Club, Charter #1243, Sacramento, CA

(in reply to cyclops2)

Post #: 82

RE: Nitro Planes A-10 Warthog for 95 dollars - 4/12/2008 2:22:51 AM

websterphreaky

Posts: 78
Joined: 2/17/2008
From: San Juan Capistrano, CA, USA
Status: offline

RysiuM,

Sounds very encouraging! Well this really makes doing the same experimenting you did, worth while. But still worried that there is no direct brushless motor replacement that would keep us from having to do the mounting mods that you had to. No lathe here to mod or make mounting parts.

A few questions -
- You said it was tail heavy. Would the plane not keep the nose wheel on the ground at all? Where did you have the 2s battery mounted?
- With the 2s battery, how much runway is needed to get wheels up if the plane were balanced correctly?
- Have you calculated where the correct balance point should be?

After your landing mishap, think we'll re glue ours. Nice recovery on the second attempt landing. Phew!

Hey, try to get someone to video your next flight with a digital camera in video mode and post it here!

(in reply to RysiuM)

Post #: 83

RE: Nitro Planes A-10 Warthog for 95 dollars - 4/12/2008 11:38:04 PM

RysiuM

Posts: 1297
Joined: 4/22/2003
From: Elk Grove, CA, USA
Status: offline

quote:

ORIGINAL: websterphreaky
But still worried that there is no direct brushless motor replacement that would keep us from having to do the mounting mods that you had to. No lathe here to mod or make mounting parts.

No need for lathe. Just get any impeller/adapter set for GWS EDF-55. It is for 2mm shaft. I will get two sets, because I think I still have some vibrations from my home made stuff.

quote:

ORIGINAL: websterphreaky
- You said it was tail heavy. Would the plane not keep the nose wheel on the ground at all? Where did you have the 2s battery mounted?

Battery was in the nose. I removed the original plywood shelf and lay the battery pack flat in the nose of the plane. The tail heavy I recognized by comparing to the balancing before the mod. The plane is well balanced it is can stay balanced on two wheels with the tail cone touching the ground. Balance point should be around or just in front of the spar visible on the bottom side of the wing.

quote:

ORIGINAL: websterphreaky
- With the 2s battery, how much runway is needed to get wheels up if the plane were balanced correctly?

I used less than 1/3 of the runway - total about 130ft, but it may need much less. I kept the plane rolling longer than it was needed.

Today I had two flights on 3S (Thunder Power Pro-lite 2100mAh). The power was insane. I added full power and the plane was flying immediately taking less than 50 ft of the runway. However there were excessive vibration. I also noticed that there is no difference in speed between full and half throttle. I was flying about 1/2 throttle and that was enough for comfortable cruse. I did some rolls - the roll rate is quite high - rolls were very easy. I did not try loops - I wonder if the wing can survive that. With 3s the balancing was just a bit to nose, but the plane flew great. Turns with banking at 45 degrees were easy without dropping the altitude. Landing was "sticky".

After the second flight the battery started to sag so I landed. Two cells were swollen. Good they did not burn. So my 3s battery pack is gone. I destroyed it right at the field - I did not want this time bomb in my truck.

The last important notice. Check your tail mount. In the tail there is a plywood plate with blind nut. It is used for screw holding the horizontal stub. This plate came loose with no particular reason. This is the same weak glue as in the landing gear. I used gold CA (foam friendly) to secure the plate back in place.

_____________________________

Mather Aerospace Modelers, Inc.
AMA Gold Leader Club, Charter #1243, Sacramento, CA

(in reply to websterphreaky)

Post #: 84

RE: Nitro Planes A-10 Warthog for 95 dollars - 4/14/2008 11:19:20 PM

RysiuM

Posts: 1297
Joined: 4/22/2003
From: Elk Grove, CA, USA
Status: offline

I found another power source fro this setting. I jumped to Walmart and got two Black Decker VPX batteries (20 dollars each). There are two A123 1100mAh in each. I made a 3s pack. The weight of the pack including wires and plug is 130g. I measured the static current - both engines WOT take 24A total. Power sounds like on 3s LiPo.

I did test flight with this battery. First I slammed the throttle and the plane nosed-over

With engines so high the nose wheel was giving enough drag to lift the tail. Second attempt was with the power adding gradually. After 50ft at about half throttle the plane lifted off and started steady climb. Wow, during that flight I did not have to use full power - not even at take off. I could make tight turns with over 45 degree banking and the plane did not sink. That''s the kind of flying I like

Rolls were easy and fast both directions. Then I wanted to make a loop. I added full power and in a split of second the plane was on its back. I backed-off on the throttle, roll it back and decided to land. Landing with power at idle was smooth and "sticky".

I found, that my receiver went nuts. Adding full power made all surfaces turn. Maybe that was a problem on take-off too. I also noticed, that moving rudder all the way to the left mad other surfaces to jump together with one engine. I''m glad I had some control over the model enough for safe landing.

The same night I replaced this Rx (Hitec Electron) with Futaba PCM. Everything went back to normal. I don''t know yet if Rx went nuts or ESC is making some weired stuff in a wires.

When I was playing with that the battery started to sink. Quite strange - from full power to almost nothing within 5 seconds. I checked the voltage - it was 7.75 without load (2.25 per cell). I charged it to 10.8V (3.6V per cell) and the battery took 1010mAh. Charging started at 4A and after voltage leveled at 10.8V the charging current was reduced gradually. It took 20 minutes to charge this battery. I like it very much.

_____________________________

Mather Aerospace Modelers, Inc.
AMA Gold Leader Club, Charter #1243, Sacramento, CA

(in reply to RysiuM)

Post #: 85

RE: Nitro Planes A-10 Warthog for 95 dollars - 4/15/2008 4:37:06 AM

RysiuM

Posts: 1297
Joined: 4/22/2003
From: Elk Grove, CA, USA
Status: offline

I think I forgot to mention one weired feature of these ESCs. I programmed the signal range from 1ms to 2ms. However motor doesn''t start till 1.2ms. When throttle is advanced slowly at about 1.2ms motor starts and than slows down and stops. After that advancing the throttle doesn''t do a thing. I had to back off to 1ms again and start over again. However when throttle is advanced fast to about 1.3ms that motor starts, then slows down and keeps spinning. Then I can play with the throttle changing the speed as long as motor spins and I don''t ho below 1.2ms. If motor stops I have to start from 1ms again.

So I mixed an offset +30 to the throttle (botch channels). When I flip the switch, both motor start and then slow down and keep running at idle speed (like a car not a jet

). Then I can fly with the switch in ON position. Even when I pull the throttle all the way back the offset keeps motors running (no dead stick landing

). After landing I just flip the switch to OFF and motors stop. Kind of cool impression is, when from idle I hit the full throttle just for a split of second. These motors jump full rpm without hesitation - immediately. It sounds like a barking dog.

I have an impression that I still have vibrations from my home made hubs not running true. At full throttle the plane sounds like 12Amp vacuum cleaner. My LHS does not have rotors for GWS EDF-55, so I asked BPHobbies about their stock. I am to much confused now about which hub goes witch which rotor. I want to order two sets and see how this improve the smoothness. Then the next step will be to reprogram ESC for reduced timing. Right now it is to much power. I can save some fling time by improving motor''s efficiency.

_____________________________

Mather Aerospace Modelers, Inc.
AMA Gold Leader Club, Charter #1243, Sacramento, CA

(in reply to RysiuM)

Post #: 86

RE: Nitro Planes A-10 Warthog for 95 dollars - 4/15/2008 5:36:00 AM

websterphreaky

Posts: 78
Joined: 2/17/2008
From: San Juan Capistrano, CA, USA
Status: offline

quote:

ORIGINAL: RysiuM

I think I forgot to mention one weired feature of these ESCs. I programmed the signal range from 1ms to 2ms. However motor doesn''''t start till 1.2ms. When throttle is advanced slowly at about 1.2ms motor starts and than slows down and stops. After that advancing the throttle doesn''''t do a thing. I had to back off to 1ms again and start over again. However when throttle is advanced fast to about 1.3ms that motor starts, then slows down and keeps spinning. Then I can play with the throttle changing the speed as long as motor spins and I don''''t ho below 1.2ms. If motor stops I have to start from 1ms again.

So I mixed an offset +30 to the throttle (botch channels). When I flip the switch, both motor start and then slow down and keep running at idle speed (like a car not a jet ). Then I can fly with the switch in ON position. Even when I pull the throttle all the way back the offset keeps motors running (no dead stick landing ). After landing I just flip the switch to OFF and motors stop. Kind of cool impression is, when from idle I hit the full throttle just for a split of second. These motors jump full rpm without hesitation - immediately. It sounds like a barking dog.

I have an impression that I still have vibrations from my home made hubs not running true. At full throttle the plane sounds like 12Amp vacuum cleaner. My LHS does not have rotors for GWS EDF-55, so I asked BPHobbies about their stock. I am to much confused now about which hub goes witch which rotor. I want to order two sets and see how this improve the smoothness. Then the next step will be to reprogram ESC for reduced timing. Right now it is to much power. I can save some fling time by improving motor''''s efficiency.