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Gliders and radio control models

Up to now I have always preferred gliders to powered models, even though I started with control line and tuned an AM25 diesel until it almost flew to pieces.

To fly a glider you need so many skills. For free flight you need to be able to interpret the wind and clouds for lift. You must design and trim the model for the mimimum glide angle and then tow and launch at exactly the right moment. I liked the mathematics of flight. If you have a slope nearby, like Ivinghoe Beacon where I flew for a while, the skills are different. You must use radio control and keep the model in the updraughts produced by the wind, going neither too low to risk landing out down on the slope nor too high to lose the model back from the slope into a down-draught.

I have done thermal soaring, both free flight and radio controlled, and RC slope soaring. There are no decent slopes in Norfolk of course but I am hoping to fly from the cliffs as soon as I have the model and the skills and the wind is between north and east.

When I started flying people didn't take many photographs. I don't have any pictures of the first five models so must rely on stock pictures.

Keil Kraft Caprice

This was my first glider. I tried to get Kenton Model Aircraft Club interested in free flight. Most members flew control line combat and speed. I organised an annual competition but it fizzled out, partly due to the fact that I always won.

Leena A/2 F1a

I flew this at the Nationals with some success. The embedded spruce spars were a pain to do but they produced perfectly smooth wing surfaces and the ribs were stronger. Wings and tailplane were covered with yellow japanese tissue. The fuselage and fin were painted blue. I used a laminated ply tongue for the wing mount that projected from the fuselage. The wings had a box that slid on, fitted between the two main spars. The tongue was radiused front and back to allow the wings to swing off either way.

Sans Egal A/2 F1a

Sans Egal

This flew beautifully and was a good test of my building skills. Flying surfaces were covered in yellow Japanese tissue and it had a painted blue fuselage.

Here is one flown by Dave Hambley to win in the Classic Glider category at the Free Flight Nationals in 2018

Photo by Mike Woodhouse

Graupner Amigo

Amigo

Mine had yellow tissue covered wings and blue fuselage. It was excellent at Ivinghoe when there was only a very light wind, even though it had only elevator and rudder.

Graupner Cirrus

Cirrus

Mine was all-white but had tissue covered wings. It was a superb thermal soarer on rudder and all-flying tailplane. It was tricky to land as it floated for ever. I still had the wings and tailplanes and built a new electric version with ailerons and airbrakes in the existing wings and a new carbon tube cored fuselage. I reduced the dihedral to about 3 degrees. Covering is yellow film from Hobby King, which I find excellent. The curvy planked fuselage has 24 gsm glass fibre applied using Eze-Kote and is brush-painted with Vallejo Premium acrylic. To see the build details click here.

Here it is:

Sirius on launch dolly

 

And here is a blast from the past. A fellow flyer in Norwich gave me his old Cirrus. As usual the fuselage became fragile so he remade the front with a very nice glass fibre repair. It is the classic original shape with just rudder and elevator and lots of dihedral. It balanced just right with two old Futaba servos, a FrSky X8R and a 4.8V NiMH pack up front. It will be weird to fly on two-channel again. I'll be towing it with the club's bungee on calm days.

 

Trio

All I have of this is a plan and two wings. It was a slope soarer that could be flown with dihedral using rudder and elevator, or with a flat sheeted wing with ailerons. I flew it at Ivinghoe even with strong winds. The plan was RM151 but is no longer available from RCME.

Phoenix

Phoenix

This was my first recent attempt to fly on local fields without help. Dustbin job. I chose a foamie as I suspected it might not last long and it didn't.

Bixler 2

Bixler

Another electric foamie. It was recommended to me by Dave Wilcox as an excellent trainer. Its only shortcoming is that being a glider you don't get any training in wheeled landings, which is still my weak point.

Wot trainer

I have converted this from an IC kit. It uses an e-Flite 46 motor.

After a small argument with the ground I rebuilt the fuselage front. The new cowl is made of balsa covered with glass fibre and film. The bottom is open for motor cooling.

 

 

ST Model Discovery

This got a good review in RCME so I though I'd try one. It went together very easily using screws rather than glue. Loads of room for the radio gear. The decals were pretty easy to handle. Even when I blundered and allowed two sticky sides to touch, I was able to separate them. The wings and rear have proved very robust but the front has taken a battering. The foam here is relatively thin and soft and a bad landing that knocks the front wheel causes damage. The supplied rudder/nosewheel servo is small and plastic-geared. A poor landing that jerks the nosewheel is also likely to damage the servo. It is a good idea to replace it with a tougher metal-geared servo.

After a crash that destroyed the nose I turned it into a tail-dragger (below). It gave me some practice with Eze-Kote, glass cloth and airbrushing, all of which were new to me. There are documents describing this on the Inventions, data and innovations page. I shortened the nose a bit so I could use 2.2Ah batteries instead of the specified 1.3 without needing balance weights.

Bix 3

This version of the Bixler has undercamber so should float well. It soon trimmed with centre of gravity a bit forward of the one specified. It is fast and responsive under full throttle, and slow and floaty when gliding. The wings are easily removable and are held down by turnbolts. This gives a lot more space for the radio equipment. So far I am very impressed.

 

Tundra

It is an interesting and attractive Durafly model kit that I am getting very fond of. It has very large flaps, big wheels and springy undercarriage for STOL. It went together easily, though two undercarriage (U/C) holes needed to be drilled out and one U/C leg thread was not fully cut. The carbon fibre propellor is high quality and perfectly balanced but I don't like the way it is fitted. It is a simple nut and there is no way of locking the backplate, which is mostly inside the cowl anyway. I now use a pair of pliers with rubber inserts that grip round the motor body. There is just enough room to get it in through the underside of the cowl.

For a fuller review click here and for assembly hints click here. Having been flying it well over a year I can thoroughly recommend it as a second trainer. As your skills develop, it is able to do plenty of manoevres. The large wheels enable takeoffs even if the grass is quite long and it will take off at just over half throttle. The undercarriage trains you to land smoothly or you will bounce. A 2200 mAh 3S battery gives up to eight minutes of flight depending on throttle.

The Durafly ARTF model is based on the Canadian Dream Aircraft's Tundra. This is sold as a kit for about US$50 000. It is made of rivetted aluminium rather than plastic foam of course. The green paint is a bit septic on the wiki photo as you can see below. The model colour green is much better. For repainting I use Italeri Olivgrun 1943 4798AP acrylic, which is fairly close to the kit colour. https://en.wikipedia.org/wiki/Dream_Tundra

Here is a picture of my pilot. Poor bloke!

 

Rudolph

After a bit of a bump I rebuilt the front of my Bixler 2 using balsa. I gave it a red nose so Rudolph was the obvious name. I removed most of the really cheap and nasty decals using strips of sellotape and then air-brushed the colour.

 

Repps Rider

This 2m model is an own design. It is for soaring off the cliffs and for tow launches using a bungee. Hence the wing roots are strong and there is a modest electric motor and battery to get me back from the sea or away from the full-size runway if blown downwind. It has a full-house radio setup. I will be building two additional 1m parallel wings to extend the span to 4m. My build record can be read here.

Acrowot foamie

I am almost running out of new things for my Tundra to do. It flies inverted but is difficult to turn. Maybe its just me. Anyway I have now commissioned an Acrowot Foam-e that I bought about a year ago. The only slight drawback is that the 2.2Ah 3S batteries won't go in with velcro and charge indicators on. So I've had to strip them off and set aside two or three batteries for this model. It's still a tight fit. The Turnigy graphenes are slightly thicker than standard lipos. It's quite difficult to squeeze the connector and lipo telemetry leads in without them touching the motor. I will add a ply plate to hold them up without restricting cooling air flow and have made a shallow battery hatch cover out of ply (picture below).

This is a model that has grown on me very quickly. I set the centre of gravity and high and low rate throws exactly as specified and it flew like a dream. It has a wide range of speeds and is very lively. Under full throttle it goes like the clappers and will do most aerobatics with less than full throttle. Using a Graphene Panther battery I get twelve minutes of flight if I don't use full throttle much, with about 25% of the energy left.

The thinner battery hatch cover

 

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(C) Peter Scott 2015

Last edit 19 July 2018