If WW1 had continued into 1919 - - - - - The Le Pere LUSAC 11

[Colin Leighfield]

As a kid I was a keen user of the library and searched out all of the aviation books. One that I loved and borrowed repeatedly was the Hargreaves publication “ Fighter Aircraft of the 1914-18 War”. Long out of publication, I recently found a reasonable copy on EBay and it had been great to pore over it once again. A great book. The first plane featured with a full page description is the Le Pere LUSAC 11, a two seat fighter. The USA had big plans for action in 1919, including expansion of the US Air Corps. They commissioned a French man called Le Pere to design a two seat fighter, to be built by Packard and powered by a 400hp Liberty engine. Originally 39 ft span, then enlarged to 41 ft, prototype testing indicated a good performance with top speed of 136 mph and good handling. It had two Marlin guns firing through the propeller and two Lewis guns in the rear cockpit. Three thousand five hundred were ordered. Two were sent to France for testing, where there were some engine problems needing sorting out. Also concern was expressed about the vulnerability of the pipe connecting engine to the radiator in the wing centre section that ran up In front of the pilot’s face. Clearly things that would have been sorted out. However the Armistice intervened and orders were cancelled with only thirty built. They were used for a number of years and one fitted with an early turbocharger and huge radiator set a world altitude record. It was “what might have been”, but the dimensions look perfect for model use. Also there is an excellent plan on Outerzone for an excellent 78” span model designed by Floyd Carter in 1974. I decided that a small quick build Depron version of this will be my final indoor effort for 2018, providing the basis for a possible indoor Nats entry in 2019.

[Colin Leighfield]

Here is a USAF museum photo of their preserved plane, plus extracts from Outerzone.

[Former Member]

[This posting has been removed]

[Colin Leighfield]

Thank you Tom, I don’t need to wait until Sunday, I’m a fool on every day of the year! If anyone doubts the scale of the US war plans for 1919 they can look for the evidence. There is a very pretty village called Talmont on the Gironde estuary just South of Royal in France. In the village hall there are laid out the US plans to build a massive deep water harbour there to serve the huge volumes of war material and numbers of service people being brought in across the Atlantic. The Armistice lead to cancellation, but there is no doubt that if it had gone ahead it would still be a major sea port on the West coast of France today. As far as the Le Pere Design is concerned, 3,500 were ordered and production had begun. Looking at detail such as the interchangeable wing panels and one piece interplane struts, you can see that it was designed for mass production. Here’s another photo of the USAF museum example and the begins of cutting bits from Depron. The build is well advanced and I’ll put more on later in case anyone is interested.

[Colin Leighfield]

The primary build material is 3mm Aero quality Depron. 2 mm standard Depron is used for elevator and rudder. The engine mounting plate is a sandwich of 3mm Depron between two layers of 1/32” balsa. The one piece interplane and cabane struts are 3mm Depron with a stiffening layer of 1/32” balsa. The wing ribs are also 1/32” balsa. In addition for the first time I’m using the new 2.5mm Delta Board from Steve Webb for the top decking and fuselage underside. More on that later. On this plane the gunner’s position reflects an interesting transition in fuselage section between semi-circular and rectangular back to semi-circular. I puzzled about how to replicate that and decided to cut and shape it from a rectangular piece of blue foam. To get the correct circular shape for the cockpit cut-out I glued on a balsa disc and set to work, it came out well and took a few minutes with sandpaper. Then I cut off the balsa disc and replaced it with a ring of 1/64” birch ply carefully cut out with the very useful compass cutters, i’m pleased with that.

The Delta Board is extremely pliable and has a smooth surface that is good for painting. It is light. However it doesn’t have enough rigidity to form a useful load bearing surface in the way that Depron does. Also I notice that the piece carefully cut for the top decking has assumed a slight “starved horse” effect, meaning it probably needed a couple of stringers between the formers. Not sure whether to live with it or cut it off and do it again. It doesn’t sand well, becoming very rough and lightweight filler doesn’t seem to fix it. I will try some watered down Ezekote and see what that does. For push rods to the control surfaces I am using carbon fibre rod with formed wire ends. This is all happening very quickly, it is my last effort on indoor for this year and I need to focus next on my build and flying programmes for the rest of the year, looking promising so far. I’m not saying the word “Chipmunk” yet, but there is a bit of brazing going on related to that.

[McG 6969]

Really cute little craft, Colin.

I guess that huge elevator will have plenty of authority.

Looking forward to your progress.

By the way, what is a "Chipmunk"???

Cheers

Chris

[McG 6969]

I think I forgot to ask...

By the way, what is a "Chipmunk"???

...

 

 

Edited By McG 6969 on 29/03/2018 10:27:33

[Colin Leighfield]

Thank you Chris! The BipeOne venture is very useful in giving me some clues in how to set up this one, including using small movements on large control surfaces! As far as what a Chipmunk is, I need to think about that one! This business of personal re-organisation is rather time-consuming! There are also elements of “putting off the evil day”, increasing my flying confidence is part of getting re-focused on the more difficult stuff. I must say though that this experiment with indoor flying has made me go back to grass roots on aerodynamic principles as well as being a quick route to getting some interesting prototypes into the air. You never stop learning.

I just noticed in my earlier post where I described the deep water harbour plans at Talmont, I described that it was South of “Royal”. Is that me or the accursed predictive text? I mean of course Royan, one of my favourite places ever since I first camped near there when touring on my Norton Commando 850 in 1975. Happy days.

[eflightray]

Posted by McG 6969 on 29/03/2018 10:26:25:

I think I forgot to ask...

By the way, what is a "Chipmunk"???

...

Edited By McG 6969 on 29/03/2018 10:27:33

One half of the team.

The other one was the Fishmunk, they worked in the Monastery kitchens, they were Friars.

.

[DH 82A]

Posted by McG 6969 on 29/03/2018 10:26:25:

I think I forgot to ask...

By the way, what is a "Chipmunk"???

...

Edited By McG 6969 on 29/03/2018 10:27:33

You cannot be serious ??

[McG 6969]

Thank you for lighting up my tunnel, young man.

But then if it were the Moneystery kitchen, one of them should show Cheaper?

Cheaps

Chris

[Colin Leighfield]

With a name like LePere, the designer could well have been some kind of a monk, very likely a friar! Not so sure about the moneystery though, more of a mystery perhaps?

[Colin Leighfield]

Is there any chance of help from a MOD? I’ve just noticed that I have messed up the thread title! It is actually the LePere LUSAC 11, not 1! I can’t work out how to edit it. I believe that the version fitted with a Bugatti engine originally intended for it was called the 12. It looks as if the 11 was meant to represent “one-one” rather than eleven, the 12 represented “one-two”. The approach to naming was interesting. LUSAC stood for LePere United States Air Corps. After the major order cancellation resulting from the Armistice, there was a report describing why it was decided not to produce any more, albeit in limited numbers beyond the original 30. It said that the plane didn’t offer enough advantage over the “D4” and “D9A” to make it worthwhile. That was obviously the US military terminology for the De Havilland 4 and 9A that were licence built and extensively used over there post war. The LUSAC was clearly not incapable though. The plane with the experimental turbocharger fitted to the Liberty engine set a world altitude record of 33,113 ft. in 1920. Later in 1921 it achieved 34,508ft, a record that stood until 1923.

[PatMc]

The USAAC don't seem to have been very keen on it from the time it was sent to Europe for evaluation. Perhaps as a fighting machine it just didn't cut the mustard, or there were other established aircraft covering the same inteded purpose that it didn't have sufficient advantage over in terms of performance.

[Colin Leighfield]

The first one sent to France had engine problems that were said to be caused by the carburettor position. Also there was a criticism that the hot water pipe from the engine up to the centre section mounted radiator would have sprayed boiling water over the crew if hit by a bullet. It wasn’t considered fit for combat. Both were simple fixes, the performance was very good and all reports said that it handled well and easily. The Liberty engine was then new and un-tested, but it later became very successful. I don’t think there’s much doubt that these things would have been resolved very quickly. It was pretty normal for very successful WW1 planes to have less than auspicious starts to their careers. (Se5, Brisfit, Fokker Dr1, they all got sorted)! It’s all conjecture of course, but it’s an interesting plane and looks pretty much ideal for a period model subject, either large or small.

 

Edited By Colin Leighfield on 29/03/2018 21:16:51

[Colin Leighfield]

I’ve found with these ultra light builds that the extra weight added by paint is a real problem. However this one won’t look right without it, so I’m testing the limits. With the open cockpits it needs some internal detail, so I’ve done some painting inside and added the gunner’s seat. It’s going to need an instrument panel as well. This is where it is at close of play tonight. You can also see the approach to the ailerons, the upper ones will be operated from pushrods off the lower pair. I can’t spend much time on this, it needs to be finished by the end of next week.

[Simon Chaddock]

Colin

That look very nice.

I suspect the US ordered LUSAC-1 in quantity despite being untested as it was an own design.

Building the successful DH9A under licence as the USD9A even with their Liberty engine always stuck in their craw a bit and like the LUSAC-1 the order for 4000 was also cancelled and only a handful were completed.

[Colin Leighfield]

Hi Simon.

I think that’s spot on. If the conflict had continued I’m pretty convinced that it would have gone into service in large numbers. With the 425hp Liberty it was tested at 136 mph flat out and cruised at 118. Heavily armed, strong and from everything I’ve read a good handling machine, it was certainly competitive. The engine problems weren’t major and the cooling pipe issue would have been resolved by running it up a cabane strut, like Albatros did, I’m sure.

Like we did and with your extensive knowledge you certainly will know that the US cut it’s air resources back to virtually nothing post war. There was plenty of stuff left lying around fit for use, scrap the rest and why buy anything new? Nothing changes really!

[Colin Leighfield]

The slowest bits so far have been working round the cockpit and cabane area. While very rough and ready by the standards of the proper scale modellers who contribute to this forum, at this size for what is really an experiment I think it will do for now. The rear cockpit has the gunner’s circular seat, the pilot’s cockpit has a bucket seat made from 2mm Depron and 1/64” ply and an instrument panel that although very basic has got the instrument holes in the right places. Fitting the top decking around that area was tricky and fiddly, but it is done. Once again I’ve used the 2.5mm Delta Board and once again I have mixed feelings about it. It is astonishingly flexible and you can fold it double without it breaking. The very smooth surface is certainly good for painting, but the Achilles heel for me is when you need to sand it at an edge. It just roughs it up and you can’t get it back to smooth. Lightweight filler doesn’t work on it. As I said earlier, I’m hoping that thinned down Ezekote will help. We’ll see.

Weight is always the bogey with models like this. At this stage including motor, radio and ailerons it weighs 51gms. Bearing in mind that the 35” span, 170 sq in. 100 gm Fairey Long Range Monoplane flies on a similar PZ type geared motor, I’m pretty hopeful that this 23” span 135 sq in. plane will finish up in a weight range that is acceptable for a steady and realistic indoor flyer. I’ve just tried to put a few photos up but when I enter my album list I can’t get the index to scroll through, which happens often. I do find the process of downloading from albums to be a real chore and also editing of posts isn’t easy. As soon as you start to type the text sometimes scrolls away so you can’t observe what you are writing in. Nor very good. I will try another post for the pictures.

 

Edited By Colin Leighfield on 30/03/2018 19:41:38

[Colin Leighfield]

[McG 6969]

Lovely little seat , Colin.

Still watching your progress, friar...

Cheers

Chris

[Colin Leighfield]

Thanks Chris, must hurry, the chips are in the pan!

[Biggles' Elder Brother - Moderator]

Posted by Colin Leighfield on 29/03/2018 19:48:44:

Is there any chance of help from a MOD? I’ve just noticed that I have messed up the thread title! It is actually the LePere LUSAC 11, not 1!

Sorry about the delay Colin - but that's done now.

BEB

PS Nice prototype - and coming along to be a nice model!

[Colin Leighfield]

Thank you BEB, much appreciated. It’s a fairly simplistic approach to build a small indoor model quickly, but I know it’s one that most won’t have heard about and I hoped that it might be of interest to some. It looks quite promising for what it is.

[Colin Leighfield]

I wasn’t happy with the results of using Delta Board for the top decking around the cabane so ripped it off and re-did it with 1mm Depron. Not brilliant but it’s reasonably inconspicuous (I hope)! I decided then to use blue foam (love the stuff) for the forward top decking and to make the “bull-nose” front. Here it is lathered with lightweight filler, most of which will sand off. The top decking will stay fixed, there is so much room in the nose below the motor and rx to position the battery, I will fit a magnetic hatch there. Next step is to sort out the ailerons on the top wing, finish it off and fit it with the interplane struts, following that with the undercarriage.

I’ve just tried to download three pictures from the album and just like yesterday, the album index won’t scroll. Perhaps it’s an IPad thing. I will try them on another email, it worked before.