TOPIC: Sabre for L2HP

A few years ago I made a profile Sabre in Depron for the L1 Rapier similar to the way I made my Depron Hawk model. I based it on Bill Dean’s Sabre Dog version and here it is alongside my L2HP powered Easybuilt Mig 15 to give a size comparison.

It flies very nicely but for some while I have wanted to build a stick and tissue model of the F86 Sabre that looked somewhat more scale than the Keil Kraft model from the 1950’s. Although the Mig is a bit draggy it nevertheless looks great in the air so this year I started building a similar sized Sabre, here is the (slow ) progress to date.

The tiny tailplane on the Sabre is a notable feature of the aircraft, however as soon as I had it together as you see here I was concerned that the tailplane was far too small (it is even emphasised in the photo). I had hoped to compensate for the lack of area by making it a thick symmetrical section, which has worked for me in the past on other models. The normal flat plate sections on these types of models is only supposed to be 50% efficient of a proper section so I thought I might be able to get double the effectiveness of a flat plate without increasing the size.

I couldn’t help doubting my reasoning for building the tailplane to scale size so to resolve my doubts I built a quick profile model of the same size in Depron with the same wing and tailplane sections to see if it actually worked. After many test glides in the garden when it was flat calm it seems to work as planned after all! Hooray, well well well! But, I suppose I will have to build a contingency set of larger tailplanes just in case it doesn’t work in anger, I will have to think of a way of easily changing them though. For the test glides I added weight to bring it up to 27 grams to ensure a reasonably accurate flight path, here are some more size comparisons.


Roger comments,

this is looking very tasty indeed, and I look forward to seeing more posts on the build. And then of course, its flying!

Have you decided whether to put the motor in a trough or a pod? Also, the possibility of genuine Jetex power if we have problems with the supply of Rapiers.

I'm still thinking about a Super Sabre for my winter build (see previous thread about this).

Onward and upwards!

Over the holidays I have made some progress building the wings, finalising the reinforced wing seating, finishing off the tail end of the fuselage and the air intak at the front end. As you can see I have started the infilling around the nose, there will be more infilling to do then I will have to carve a plug for the canopy.

This is shaping up very nicely indeed. Any idea what it weighs at this point - do you have a target weight?

I really must make a start on my Super Sabre!

Thanks, I have deliberately built it on the tough side but with light wood (if that is not a contradiction) the current weight of the balsa is 17.2g and am hoping to keep to 18g finished. I expect it rise to double that when covered with Airspan and airbrushed ( I haven't decided yet on a final scheme) so probably the flying weight will be around 40g, one can hope. My Aristo-Craft Swift is 43g and that flies pretty well but it will all depend on how draggy this one turns out to be.

The material I have used here on this first trial run at moulding a canopy was scrounged from wife’s craft goodies, it looks like PVC and moulds very well and early results looks like it will glue OK. At .25mm It was too thin to use with the plunge method so this is my improvised Heath Robinson version of a ‘pull down’ method. This requires an operator with multiple arms like an octopus so I have to improvise with rubber bands and weighty clamps to hold the edges down. This is not quite the final version as I want a better fillet all round the bottom of the canopy which I form with a plate with a hole that is tight fit on the lower periphery of the canopy. The edge of the hole is carefully radiused to give me the fillet and is done as a final operation once the canopy has been formed, locally heating one side at a time with my covering hot air gun. It seems to work, but next time I will have to keep the dust off!

The Sabre is nearly ready to cover now with a couple more bits of infilling to do and plenty of sanding. I have been looking at colour schemes for some while but am still undecided. I have always wanted to model the Sabre that I saw flashing around over the Thames near RAF Benson in the mid 1950’s on a dull wet day, no doubt showing off what a Sabre could do when the RAF first had them. Despite the dull camo maybe now is the time to do it, we’ll have to see!