A10 plus

[Martin McIntosh]

I have been bashing on with the u/c pods which are now done and the first one film covered. Not easy as expected. Once these are completed and fitted I can work out the nose leg length and get the mount made.

Stopped work on the nacelles because I need some fresh release wax and a new lot of gel coat in order to do them properly. These are now on order.

I seem to be getting through a fair bit of a Banggood 5m roll of covering film and there are still a lot of fiddely bits to go, plus the fus.

[Martin McIntosh]

Got the wing covered and the u/c pods fitted. The hard part is the nose leg which has to retract rearwards because otherwise the battery would be in the way. It is being fitted in the nose cone so as to keep it from intruding too much on the battery hatch. I am trying to work out a way of keeping it central during retraction since all of the HK units have lousy geometry regarding the steering arm so I shall be using pull-pull. If this does not work I shall simply make it fixed.

 

 

[David Hazell 1]

Lovely lovely work there!

[Martin McIntosh]

Thanks, I have now installed the steering servo just in front of the wing LE. I have a cunning plan to keep the leg central but if it does not work I shall whip the thing out.

[David Hazell 1]

59 minutes ago, Martin McIntosh said:

Thanks, I have now installed the steering servo just in front of the wing LE. I have a cunning plan to keep the leg central but if it does not work I shall whip the thing out.

 

Make it scale and stick the leg on the right hand side?!

[Martin McIntosh]

After very many fits and refits I have got my nose wheel centring to work properly. When retracted, the springs keep tension on the closed loop. The wires have now slackened off since fitting so will require re tensioning.

The nacelle moulds are still causing many problems but I think that I can now get round those.

Awaiting the nose block glue to set so that the fus. bottom can be enclosed and shaped.

 

 

[Martin McIntosh]

After much hassle for some reason I have at last got a set of nacelle mouldings after reverting to my old method of producing these. They are from a single layer of 160gm/sq. m. cloth and are vert light.

I decided to glue the N4 parts inside them so that they can be screwed in place, thus giving access to the fans.

I had to make a canopy from very expensive balsa so it is a bit skinny and none too scale.

 

 

[David Hazell 1]

Loving your work. I made the mistake of gluing everything into the engine pods and have no access now which was the wrong move. I discovered my 950g thrust 35 amp edfs are only pulling 22 amps so I guess only making 600 odd grams of thrust. 

 

I've finished my plane for all intents and purposes now, only remains to get it maidened! I'll post pics of the finished model soon.

[Martin McIntosh]

What make of fans and escs are you using? I believe that the esc timing needs to be set to high. I may well run into the same problem myself since I am now at the stage when I can make up the wiring loom and check what is happening.

[David Hazell 1]

3 hours ago, Martin McIntosh said:

What make of fans and escs are you using? I believe that the esc timing needs to be set to high. I may well run into the same problem myself since I am now at the stage when I can make up the wiring loom and check what is happening.

 

a couple of these: https://uk.banggood.com/QX-MOTOR-50mm-12-Blades-Ducted-Fan-EDF-CW-CCW-with-QF2611-3S-4S-Brushless-Motor-for-RC-Airplane-Jet-p-1569275.html?rmmds=detail-left-hotproducts&cur_warehouse=CN&ID=51187045905&trace_id=c8441680542047345

 

[David Hazell 1]

 

Did a quick maiden - worked a treat! I didn't have the guts to fly it myself, I got my mate Toby to do it as he's an awesome pilot. I didn't get the whole flight unfortunately.

 

 

[Martin McIntosh]

Well done. I like the colour scheme; unfortunately mine will look rather more plain until I find out if it actually works.

[Martin McIntosh]

Now that I have the wiring done I have been testing the fans. The stated wattage per fan is 628 but with both running on a full charge I am getting just over 1kW. This soon dies a bit as expected since the batteries were intended to be used in pairs on outrunners and the connectors are only XT60`s, not 90`s. The static thrust is enormous.

Got myself in a pickle with the screwed on rear nacelle parts. With them on I cannot fit the thrust tubes and if I do it the other way round I cannot get at the screws! Found a way round it.

The fans are quite heavy at 135g each and the wiring to the ESCs is also weighty since I did not wish to extend the battery leads so I shall later find out if this affects the cg.

I can now fit the elevator servo and finish off the covering so still plenty to do.

[David Hazell 1]

I tried to get mine to rotate off a grass strip the other day. Mulch on strip not good for edf! The mulch clogged a fan and snapped the central mounting screw on one of the fans! I think I had it screwed down a bit too tight which probably weakened it. I've replaced the m2 screw with an m2 allen (all I had). I can't realistically balance the cone and fan now (access issues!), so it might be waiting to shake the plane to pieces. Waiting for less wind before I try again! 

[Martin McIntosh]

I know the problem only too well. I watched TN fly his Concorde from the BMFA centre patch and it went off fine which prompted me to build one since I have a TN Vulcan with cheapo HK fans. I could have walked faster than it was on grass but was able to test fly it at Barkston. Despite my efforts I have not been able to get at the fans to upgrade them.

I tried the Concorde at my local patch; it would have gone if I had let it but there was a noseleg problem. Tried again but there was mulch on the patch and it ground to a halt with all four fans clogged up. Need to put FOD guards over the cheat holes before I venture out with it again.

Hoping that with a proper u/c to raise it the A 10 should be OK.

[Martin McIntosh]

Got mine to the point where it could be maidened when I can. Lots of problems have arisen recently, mainly the fact that with the rudders linked up the linkage jammed at the servo end due to it fouling on a tail rib. No choice but to take a saw to the rear end, replace the smelly burnt out servo and sort out the problem.

For some reason the nose leg has gone in to one side and fouls but easily corrected.

Now it was crunch time. Luckily a 4s 5800 easily gets the cg correct but I may need to bend the main legs rearward a little.

Scales next. I could not possibly have built the airframe any lighter and was hoping for 5lbs but it is actually 5lb 13oz. Still fairly chuffed with that though, considering that it is much larger than the original.

Some pics in my shed since it is precipitating down outside.

 

 

[David Hazell 1]

Brilliant! Let me know how the maiden goes! I too had to perform extensive surgery on the back end to get the servo moving freely, but luckily it didn't end up with a burnt out servo. Having a rudder definitely helps me though as mine is a tail dragger and I can get it pointing the right way whilst gaining enough speed for take off.

 

I will hope to fly it again this weekend, weather permitting.

[Martin McIntosh]

Hi again David,

I have had a few expected problems with the flimsy nose leg but now hopefully sorted.

With the stated cg %age from the LE the model would sit on its tail if pushed down. Fixed with a couple of washers under the front of the main units. As above, I had to guess at the position of the legs.

Due to some eyesight problems having cropped up it may have to join my queue of unflown projects, but not having flown anything at all since last September I took up a fun fly a couple of weeks ago OK, so with the blacked fan nacelles it should be visible enough. (And yes, I did warn club members flying on the same day that I could have problems).

Empty bench now and a cartoon style military drone is on the way with some rather unconventional construction. Watch out for `Dr. One`.