e-Hawk 1500 ARF “build”

[Mucksmear]

Grabbed a photo off the interweb and did several quick paint-overs to see what might work. Also may paint a straight edge into the bottom of the canopy/hatch.

For the past week, I was positive I was going for the 1st trim scheme until last night. I’ve finally settled on this last one using transparent yellow, orange and red. Been a long time since I’ve used any transparent colors. I imagine the colored areas will be a little darker since the underlying balsa isn’t white, but the open wing bays behind the D box should light up nicely when thermalling.

 

[Konrad]

And if you don’t like the V-tail response (my issues are usually directional control not elevator power) it’s easy enough to correct at a later date.

 

[Mucksmear]

And if you don’t like the V-tail response (my issues are usually directional control not elevator power) it’s easy enough to correct at a later date.

Agreed!
Interestingly, IF i did my measurements/calculations correctly, the ehawk has the following equivalent tail volumes:
Vh=0.455
Vv=0.021
which makes it a little more generous than the old-school Coyote or the Ridge Runt (assuming I did ran those correctly).

 

[Konrad]

My Coyote needed a bit more aileron diff than I liked to keep on heading. And if allowed to run, wandered a bit. So it looks to me the Coyote needed a bit more rear vertical area. Did your calculations take into account the aspect ratio of the wing? The Coyote has a lower aspect ratio wing than this ship.

 

[Mucksmear]

My Coyote needed a bit more aileron diff than I liked to keep on heading. And if allowed to run, wandered a bit. So it looks to me the Coyote needed a bit more rear vertical area. Did your calculations take into account the aspect ratio of the wing? The Coyote has a lower aspect ratio wing than this ship.

Interesting- I will have to look out for that. I’ve never flown a Coyote for any meaningful length of time, but I think I may have upped the overall tail volume on my V-tail converted Coyote.

Yes, my calculations took into consideration wing aspect for both my Coyote (and stock per plans) and this eHawk

 

[Konrad]

Small world. At one time I too did a V-tail Coyote . More to keep the stab out of the weeds. With that Duralene fuse nothing stuck to it. I recall servo trays and tail feathers being difficult to keep in place.

 

[Mucksmear]

One recurring issue about the ehawk I’ve read is the tendency for the vacuum formed canopy/hatch to heat up and distort in the sun. I like having the black section to indicate the canopy so I figured why not make a fiberglass canopy that’s a little more robust. It could still suffer the same fate but what the hey.

Couple layers of 3/4 oz followed by a layer of I don’t know, 3oz? Seems stiff enough and is of similar thickness as the supplied canopy.

The black marks are from the sharpie I used on the cloth to mark my shapes

Female mold removed

Edges tidied up

Laying up the canopy. A little Cabosil mushed into the corners around the cooling air intake

 

[Mucksmear]

Started covering the wings this evening. Still waiting for the back ordered transparent red to arrive.

Each section of transparent color will overlap the adjacent panel by 1/8” along a rib. Pieces are cut to size and taped into position.

Key is making sure the piece is laying down evenly across the span and chord before ironing along the perimeter.

 

[Konrad]

What covering material ( type or brand)?

 

[Mucksmear]

Hangar 9 Ultracote.

 

[Konrad]

Wow, August!! Let me know how much you need (dimensions). I’ll look in my attic to see if I have any partial rolls.

P.S.
I have a partial roll that I labeled Parklite 966.

PM me with your requirements if you are interested.

 

[Mucksmear]

Thanks much appreciated but I think I am set. Transparent red shud arrive in a couple weeks, meanwhile there are other tasks remaining.

I believe “parklite” is their lighter weight covering for small parkfliers etc.

 

[Konrad]

Yes it is about 2/3 as heavy as their transparent Ultracoat . I use it on many of my 3 meter plus ships in an effort to keep some weight out of the tips. Now it is about twice as heavy as Solar Film‘s So-lite (aka, Nelson film). I find that Park light stands up to the weeds and rocks around here just as poorly as full weight Oracover (aka Ultracoat). So I’m recovering the wings at about the same rate anyway.

 

[Mucksmear]

Interesting and good to know. Your 3 meter ships are slow flying open structure floaters or faster heavier slope ships?

My last real use of transparent film was the old formulation of Monokote which while seemingly stronger and less stretchy than Oracover/Ultracote, was still poor performing against twigs and branches

 

[Konrad]

I have both. But for this discussion I was thinking of the open structure like the one you have here. Some designers thought that the heavier Monokote added torsional strength, never saw it. If using a fully sheeted wing then I don't think it makes any difference and I for sure would go with the nicer handling Oracover lite. BTW; I hated Monokote and despised it's later iterations! Even 30 years ago there was a good reason firms like FVK used Oracover over Monokote. I liked Solar Film products other than the tendency to have the color/adhesive delaminate from the film over time.

 

[Mucksmear]

Transparent fluorescent red Ultracote arrived - finished covering the wings and ailerons. I like it.

Also soldered up the connectors for the ESC and motor. Motor fits nicely with enough room for the wires coming out of the motor to trail back without a tight kink and without rubbing against the rotating bell.

Since I’m going elevator only on the V-tail, I needed to make a new single input pushrod. 3mm carbon tube with the stock Z-bend wire end at the servo and a pair of threaded ends for clevises at the elevators.
I scuffed about 1” of the wire ends and the carbon tube before slathering with JB Weld. A spiral wrap of wire-wrapping wire lashes the wire ends to the CF tube and a piece of heat-shrink tubing finishes the assembly. The heat-shrink gets the JB Weld to flow a little and squeezes the excess out.

 

[Mucksmear]

Got the gear inside. Running one antenna along the inside of the fuse opposite the elevator servo and pointing aft.

To clear the battery and motor I’m running the other antenna spanwise in the wing through a length of Sullivan gold-n-rod inner housing (just visible through the enlarged exit hole for the servo connector). Wing has a small diameter carbon front spar. Will see if this is an issue at range test.

I had to reduce telemetry power on the GR6 to get the HS-65mg elevator servo to stop clicking. Tried wrapping the rx in foil, twisting the servo leads, etc before stumbling on a related GR6 thread in the Aloft forums.

 

[Konrad]

Hum, the twisting of the leads and the foil didn't work. I'd have given better than even odds that it would have.

 

[Mucksmear]

I needed a way to secure the battery so as to avoid inadvertent changes in CG during launch or landing, etc.
I ended up with a 1/16” ply floor plate to provide a flat mounting surface for a bit of 3M Dual-Lock (or velcro). In the past when I used adhesive backed velcro, one piece had to be stuck to the battery to prevent it from sliding but this also made it difficult to use the battery in other installations unless the velcro happened to line up in the alternate installation. To get around this problem I made a battery sleeve out of fiberglass reinforced tape that I can slide the battery into. The strap has a length of Dual-Lock on one side. A bit of masking tape can be used to prevent the battery from sliding in the sleeve.

CG is now sitting around 60mm back from the LE at the root. Others have reported that the manufacturer suggested CG of 53mm is too far forward. Scott’s 1st flight seems to have confirmed this. I’m now ready for a range test

Incidentally, the GR6 rx I’m using has altitude and V-speed but no Vario tone, is this something I can upgrade with firmware or am I stuck with being vario-less on this one?

 

[Wayne]

Another great little idea.