Bedfordshire Silent Flight - The DH60 Cirrus Moth project by George Parker.

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The DH60 Cirrus Moth

In the January (1996) issue of Aviation Modeler is an article by Mr Don Harvey on how to make the DB Sport and Scale Moth 40 kit into a very near scale model of the DH 60 Cirrus Moth G-EBLV that is part of the Shuttleworth Collection at Old Warden. AHHH! HMMM! I said to myself, I likes the look of that and what's more, I've got a Moth 40 kit part built in my shed somewhere! So after about half an hour of rummaging about in my shed, lo and behold I had the wings, fuselage, tailplane, elevator and rudder already built. OK, so some of the bits had fallen off because the glue had dried out and the wings needed joining, but I could soon fix that couldn't I?

Now then, what about the motive power? The kit calls for a 40 - 50cu.in. four stroke, but me, I'm going to be different! I'm going to electrify it, ain't I? So I ask myself, what motor would I need and how many cells? Now, as I'm not a very rich man and I can't afford one of those all singing, all dancing cobalt or neodymium motors, I must admit I was stumped for a few days until I read the February Electric Flight International. There, right before my very eyes, was the answer in a plan reviewed by the designer, Paul Rossiter. His Hammer E design makes use of the low cost Graupner Speed 700 Turbo BB 9.6v motor with an adapter plate that lets you fit a cheap MFA Olympus 2.3:1 belt reduction unit. This he says will give reliable performance with up to 14 x 1700 mAh cells and will give enough power to suit a 40 size i.c. model; just what I was looking for!! So off I went into my shed. After kissing the wife goodbye and saying that I would see her in about 2 weeks and could she keep the tea and sarnies coming whilst I was migrating, I started putting the thing together.

The wings went together well and I had no trouble making the ailerons. (These need cutting out of the built up wing and can be tricky if you're not very careful.) The next step was to lighten the fuselage. There is a lot of block wood that forms the nose and the fuselage sides are made of ¼ balsa and 1/16 plywood, all very necessary if you are going to fit an i.c. engine but not if you're going electric. So out came a lot of the block from the nose and I also cut holes in the fuselage sides, tailplane and elevator. This took about 1 lb 2 oz off the uncovered airframe. Worth doing as I was going to add scale detail, not a lot, but enough to look like the full size thing.

Having completed the airframe, the next job was covering. So off I went to Jeff Stubbs at Oundle to see what he had in store. After having a good old natter and looking at this and that, we decided that ocean blue gloss-tex was about the right colour. Jeff even went upstairs to fetch a book that had a picture of the Cirrus Moth in it so that we could be sure that I had got the right colour…..now that's what I call good service. I also purchased some matching solar lac for the cowl, wheels, interplane struts etc. and some silver gloss-tex for the wings and tailplane.

Covering wasn't too much of a problem. I've got a small travelling iron that I use and I must say it makes a lovely job so long as I use the lowest temperature conducive to getting a good bond to the airframe. The lettering was cut from gloss-tex and the moth motif was hand painted (not very well) but looks OK on the finished model.

Next step was the motor and gearbox. I already had the motor but I needed to purchase the gearbox. Looking through the mags, I saw an advert by Hillcott Electronics for the plate and belt conversion set for the MFA gearbox, but when I phoned, they hadn't got the plate or belts in stock. They had a gearbox made by Graupner for the 700 type motor so I decided to have that. When it came it looked massive, was quite heavy and cost £36, but as it fitted the motor and into the model, I made up my mind to use it. This motor and gearbox gives bags of power with 14 x 1700 cells and a 13 x 7 prop so the extra cost was well worth it.

The completed model weighed in at 7 ½ lbs and I wasn't at all sure it would fly, but it did. After waiting several weeks for a reasonably warm day and being sure the man upstairs didn't want me to fly it, finally a day came that wasn't so cold, but it was windy. So off to Thurleigh my brother and I went. He had completed a Sea Fury and was also waiting to test fly it. When we arrived, the wind was a bit stronger than we would have liked, so we decided to test fly the Sea Fury and then I would taxi the Cirrus Moth to see if it ran straight on take off. Well, it did run straight and it did take off much to my surprise!! Well b****r me I said to myself (or words to that effect). Its up there now, so I might as well fly it around for a while and fly it did, and very well until I let it get a bit far away. Then it started ducking and diving all over the sky. So I throttled back and decided to try a down wind landing while I still had some sort of "control". I managed to get it lined up with the runway and in the perfect attitude to land but I had misjudged the distance and landed in the grass. As soon as the wheels hit the grass, the model somersaulted about 4 times, pulverised the rudder, badly damaged the carbane struts and fuselage sides, but the wings and tailplane were undamaged. All in all it could have been a lot worse, couldn't it? But I think the thing that hurts most was the realisation when we were getting the bits back that, in my excitement at seeing the model take off, I hadn't raised the aerial on the transmitter!! No wonder it went haywire. It just goes to show that, no matter how long you have been flying model aircraft, you can still make the proverbial balls up.

The model has since been repaired and flown, but it doesn't look as nice as it did before the crash (not to my mind anyhow), but it does prove that you can stick electrics in most types of model aircraft and have a very nice flying machine that is not noisy and doesn't get all messed up with sticky fuel……but it's not cheap.

Costs

9.6v 700 bb turbo motor	£20.95
Power gear 2:1 belt drive	£38.95
14 off 1700 scr cells	£69.90
DB Sports & Scale Moth 40 kit	£65.00
Solar-tex silver	£10.00
Gloss-tex blue	£20.00
Solar-lac	£ 5.00
Wheels scale type	£10.00
Total inc £5 p&p	£244.80

And you have still got to count the radio, battery charger etc., but if you can afford it, go for it. It's great fun.

May all your landings be good ones.

George Parker