Gremlin by Aeroic

[Peter Garsden]

[Peter Garsden]

I bought the Gremlin on Facebook from a chap that bought one of the first out of the moulds but had never assembled it. Beautifully made as usual from Doc Hammond.

The blurb says it files in more or less any wind and is very aerobatic. I can confirm as I have seen one fly on You Tube.

The kit has much more room than most of the range for gear and servos.There is a ballast tube included but I am not sure where it goes. I am just going to use ballast in the wing. The large carbon joining tube can be filled with wooden blanks or brass rod. I work out that it needs 15mm which I am going to order from Ebay.

One has a choice of either 2 servos up front, or one in the front and the other in the back with direct connection to the elevator. There is also a choice of either a pivot for the front access method or the rear mounted servo attaching direct to the elevator. I am going for the latter using a similar method to the Stormbird.

[Peter Garsden]

Another Gremlin question sorry. How does one block off the ballast wing joiner tube yet get the tube into the wing without binding? Block one end off? Plug the other end but how? One cannot use a screw or plug because it would bind on the wing tube

[Peter Garsden]

Have now made some progress with the Gremlin which I think will not be difficult to put together - more room to play with than the Redshift and other F3F planes - always helps

Here you can see the Rudder servo in situ connected to the carbon snake which has been cut to size. The servo is fairly inexpensive KST but will take the load I am sure - very freely running snake and tube to the rudder. I used the wonderful method advocated by Doc Hammond namely cyano the carbon rod into the screwed end attachment, having first threaded over some shrink tubing, then glue the tubing in place with epoxy and wipe off any excess with Methylated Spirits and shrink the tubing with a soldering iron rolled over.

You can see that I filed out the receiver slot so I could pass my rx through it for access before assembly. The battery which is a flat pack will have to be fed down the gap behind the Multiplex sockets

[Peter Garsden]

I also spent yesterday making up some leads for for wings - the sockets rest on a ply plate in the fuselage attached, methinks, with hot glue - the instructions called it Liquid Tape, which sounds the same? This will strengthen the wire attachments and stop them deteriorating with use. I will also hot glue the wing plugs to reinforce them as well.

[Peter Garsden]

The rudder definitely needed sanding down to give it more movement - both the outer frame and the wipers so now I can get a good 35mm out of it which should be enough

I thought I would have to file back the clevis to stop it binding on full right movement but not so in view of the slot in the wiper as you can see here.

I filed down the fin edge to stop the rudder binding on full left throw

[Peter Garsden]

I got a lot of help from the Aloft hobbies blog here https://forum.alofthobbies.com/index.php?threads/aeroic-gremlin-build.273/ - it shows you how to build a support for the elevator servo so that one can mount it inside the fin. The control rod needs to move in the same arc as the elevator which means the connection needs to be inside the wing.

I am using a Ripmax SD150 servo left over from my D40 which hit the deck and disintegrated recently - another story. I glued it to a 3mm liteply plate with 1.5mm ply side supports. The idea is that one attaches the control rod to it and threads it into the fin then lines it up with the elevator before gluing it, then screws go into the hole. It sits on a circle of balsa so its angle can be adjusted. The support is a sandwich of 3mm ply and balsa to lift the assembly off the side of the fin.

This shows the position of the servo when in situ with the rotation of the arm lined up with the arc of the elevator.

Edited By Peter Garsden on 27/01/2019 12:08:17

[Peter Garsden]

I am puzzled as to how to keep in position the rear elevator pushrod clevis because it sits inside the tailplane and will be nightmare to find once the rod is removed. I think the tailplane must stay in place.

I have used the same method as the Stormbird but am not sure it will work. The Stormbird fin is very narrow so it works.

I saw a method on the Aloft Hobbies site which showed a Z bend shape at the servo which may have been the answer I don't know.

Any thoughts?

I had to file the clevis so it wouldn't bind the bottom of the fin.

[Peter Garsden]

I didn't post the first wing but thought I should post my thoughts on the wings.

I am using the KST servo bearing supports, as there is no support for the servos in that the wings are quite deep in section. The instructions show quite a thick piece of balsa attached to the upper skin and servo to stop it twisting in its seat. The bearing kits prevent this and work well.

One has to rough up both the underneath of the housing, and the surface of the wing.

I use 2mm studding which needs bending to fit the profile of the wing.

[Peter Garsden]

Because the wing root is quite deep, I saw on the Aloft Hobbies blog that a piece of 6mm balsa to support the Multiplex plug is a good idea. Presumably, it stops the wires chaffing and fraying on the edges of the wing root.

Maybe the idea was to glue the plugs in position, but I will leave them loose

[Peter Garsden]

Managed to maiden this today but more of this later.

I followed the recommended wing retention method of a rubber band between 2 hooks in the wings and a dowel which is already glued in. Worked a treat.

I glued in an electronic switch with hot glue which means you don't have to detach the canopy each time.

[Peter Garsden]

It was a bit of a mad rush and I didn't have any ballast but the forecast today was for 17mph Southerly. When we arrived, however, the wind was none existent and South East, so we waited a while and eventually it got to 11mph max. It was strong enough to try a maiden.

So I chucked it off and it needed no correction, just sailed away. It flew well even in light wind. I tried the thermal setting but it dived because of the down elevator mixed in.

There wasn't enough aileron even though I had followed the recommendations of 10mm up and 7mm down. I have now increased it by about 30%

Unfortunately, when engaged the crow brakes the ailerons didn't work. This resulted in a heavy landing as it went into a right hand spiral dive.

I didn't have enough lift to try any aerobatics other than a quick loop.

When I looked at the settings I realised that I had only selected about 35% movement for the ailerons in dual rates and that the butterfly setting was asking them to move 98% - so there was no movement left. When I increased the amount of movement, and reduced the throw the ailerons started to move in the crow setting when engaged, so it is now sorted, but I want to check they work at height not close to the ground.

It needs more wind and better lift to assess its potential properly. I also need to glue in the nose weight - I moulded the shape of the nose in wet sand and poured in molten lead - I also need to cut up the ballast.

[Peter Garsden]

Just to finish this off, I have made a couple of stickers with the Inkjet printer then sprayed with Acrylic Varnish to seal the water out. Thanks to Doc for sending the Aeroic Sticker, which I changed to a white background, hope you don't mind. Should really have printed the Gremlin Sticker on a white background. Might still change it.