Avionnette HM-8 build thread.
 

Hey all,

I received the plans for the HM-8 today. They're pretty well drawn, and apparently there was a construction article in a RC Model World publication back 1995 as the seller was kind enough to include a copy!

I spent a long time staring at the plans, and the more I look at 'em, the more I'm thinking that I'll be able to build the plane just as designed and get away with putting the G-Mark .12 Twin on it. I'm a little concerned with the 3 ounces of extra weight up front, but since the designer claims it has the potential to come out tail heavy if you're not careful, I'll just take less care in that area. ;)

So whatta ya'll think - am I crazy to think that I can just build it at this scale and run the .12? It is a fairly good size model for an .049 with a 44" (or 50" optional) wingspan.

Oh, here are some engine weights for comparison:

Cox .049 Black Widow: 2 1/4 oz.
G-Mark .12 Twin: 5 1/4 oz.
OS .10 FP w/muff: 5 1/2 oz.
OS .10 FP w/o muff 4 3/8 oz.

RE: Avionnette HM-8 build thread.
 

I like the HM-8 much better than the Pou du Ciel. Less of a flying joke, yet still cartoonish enough to appeal to my warped sense of aesthetics. You can find some pictures and original drawings at http://jolly.roger.free.fr/ -- as miscellanies on this Pou du Ciel site.

I'd go with the G-Mark twin for the cuteness factor and at least making your nose weight functional. It should haul your plane around almost as well as a Black Widow. ;)

RE: Avionnette HM-8 build thread.
 

It's got a short nose and a lot of junk in the trunk - why add useless weight when you can add looks. The twin would look great in there.

RE: Avionnette HM-8 build thread.
 

PBJ, I would go with the .12 and the bigger span. I think it would look good with transparent blue and green covering on the flying surfaces.

RE: Avionnette HM-8 build thread.
 

Given that the design was intended to fly with the 049 slogging along with an 8 inch prop on the engine And that you're going to be using the .12 with a more normal size for that I'd have to agree that you could easily and SHOULD make it a little larger to avoid it coming out overpowered. But it will only need a little increase. It'll depend on the wing area presently but I'd say that a bump in size to generate up around 400 to 440 sq inches would be a good way to go. That'll ensure you retain the "powered glider" performance level but with a little care you should be able to keep the weight down to around 2 to 2.25 lbs. It IS pretty much a free flight model after all.

I sure liked the looks of that version with the engine mounted on the birdcage like mount in the other Gmark thread. I'd seriously be looking at converting this model over to that style of nose. For the mount I'm wondering if you could silver solder it from a heavier wall brass tubing. Like the 1/4 inch stuff used in some plumbing fixtures. Or if you could find some small aircraft chrome moly tubing.

FOUND IT! Aircraft Spruce and Specialty. 3/16 seamless chromoly tubing with .028 wall. Silver solder together using a MAPP gas torch. Oh heavens.......

http://www.aircraftspruce.com/menus/me/steel.html

RE: Avionnette HM-8 build thread.
 

Neat project, PBJ. Very classic. The twin should add a lot of style and class to the plane.

RE: Avionnette HM-8 build thread.
 

Oh, darn you Bruce - you're not going to make this easy on me, are you? ;)

As is, the model can be built with a 50" span, and with a 7 1/4" chord that gives around 360 sq. in. IF I could build it 28-32oz, I'd have a wing loading around 11-12 oz/sq ft - not bad. The G-Mark only spins a 7x4 in the low 13's, and it does have a throttle, and, and... I really was hoping to avoid the re-engineering, and get away just building as - is. A 110% model would give me 55" span, almost an 8" chord and 440 squares - right at your magic number... but what do I do about the odd material sizes?

I do like the built-up engine mount, but with the little time that I have to build, it would be another complexity that would slow things down, way down. (But man, it would be just the ticket wouldn't it?) Decisions, decisions...

Oh, CP's right on the covering choice - a model like this needs some transparent covering to show off the structure, but blue and GREEN? [:'(] Nah, maybe opaque white and transparent blue. [8D]

I'll hit Office Depot this weekend and see what it would take to bump this up 110-125%, but I'm not making any promises.

Thanks for your support guys - I think. ;)

-Joe

RE: Avionnette HM-8 build thread.
 

There is quite following of the Pou du Ciel of which the HM-8 is family member. I have always thought the Flying Flea a neat design and once built an Ebenezer version of one from a plan I found - might have even been a Steigler plan.

Anyways, I think the HM-8 is nicest looking one of the bunch and the nicest looking full size one I have seen is (or rather was) a Swiss registered HM-8 HB-YEI - wings looked like they were clear doped linen with dark red / maroon leading edge and the fuselage was a dark red / maroon / mahogany and yellow or gold colour; very sharp looking indeed.

Pictures here: http://www.avion.ch/hm8/images.htm

So, if it were me - use the G-mark (although I have PAW 1.49CC that would fit the bill rather nicely), perhaps enlarge it perhaps not, cover with a fabric or silkspan (in fact I would use silkspan or silk over mylar) - clear dope the wing (with a slight tint of cream to get the off white look) and maroon like HB-YEI. If were me of course.

Now you got me thinking of whipping together an Ebenezer HM-8, would that then be a Pou de Ciel-enezer !?!

cheers, Graham

RE: Avionnette HM-8 build thread.
 

Easy? WHat's that??????? :D

I had no idea that this was all it would do.

OK, you win. 360 sq's isn't that bad. As long as the engine looks "scale" to the plan then go for it.

The wood usually isn't where the weight comes from. Generally it's the hardware that can add on the avoirdupois quickly. But stick to lighter grades and plan on using something light for covering and go that extra mile to get lighter hardware and it should be practical to hold it to 24 to 28 oz.

If you're going to use functional rigging then a LOT of the need for our classical structural strength ceases to be an issue. Wing spars can then be made quite a bit lighter. Also the center A frame wing mount can be done quite lightly but you still want some good flexibility in there, Not for flight loads but for twisting and "arrival" loads. Carbon tubing would be a very good choice for this. And the wing mount only needs to locate the wings rather than withstand all the bending loads since the flying and landing wires will take care of that.

I still need to dig out that wire. I'll make it a point to look for it tonight and let you know. But even if it turns out that my wire is all twisted and shot Brodak has control line sets. But let me check my parts box first.

I'd also suggest that you alter the airfoil to round that nose a little. Sharp nose shapes like that one are often known for having a harsh and abrupt stall.

I'm not sure what the wood sizes are that they call for. A good indicator that it SHOULD be quite light is the fact that it was intended for .049 and Scale Texaco flying. The rules called for a minimum 8 oz/sq ft loading. I'll bet it can be built pretty close to that and then you just add the Gmark. But pick that wood carefully so it hits the mark. With some superhuman care it may even come out at 10 oz/sq ft..... :D

RE: Avionnette HM-8 build thread.
 

Don't forget that you will gain structural strength from the covering materials also, so don't bang your head around too much on the wood sizes. Keeping the hardware light will go a long way to better flying BUT don't expect any heart pounding aerobatics with that parasol wing.

This plane will fly very well as drawn, so don't try to make it something it's not. These pioneer designs are limited in what they will do. Any chance of duping the plans and sharing with your balsa brothers? I'd sure like to build something like this myself.

RE: Avionnette HM-8 build thread.
 

How about an opaque cream for the fuselage, fin, and stab with a translucent blue for the wing, rudder, and elevator? Blue accent lines on the fuse and other cream surfaces.

RE: Avionnette HM-8 build thread.
 

Tranluscent yes. Transparent? PLEASE NO! ! ! ! While clearly transparent looks nice on modern gliders and stuff old classic designs really need a "privacy glass" like translucency so they don't end up looking like flying fishbowl's.

Something like Litespan with the fibers in the material would be excellent. And for a color scheme I'd say keep it simple since the lines of the model will be entertaining enough. Some fake registration letters rather than numbers to show it's European heritage would be nice. Something like F-PBJF would be a good fake French registration with the first F being for France and then you need 4 letters to fill it in. On the fuselage I'd keep it simple so the structure showing through can be seen with less "clutter".

With a little care this thing will be very "Lazy Bee" like.

RE: Avionnette HM-8 build thread.
 

What? Didn't you see the "after Bruce" video in the G-Mark thread? [X(]

Oh thank you! I really didn't want to mess with scaling it up and substituting materials, and wonder what wood sizes should go where, etc...

The twin is a given, and I think even at the current scale it will look right at home. I got to thinking about mounting the engine up high on a fab'd mount, but what would I do for a fuel tank? It's not like I could run gravity feed with a wing tank! ;) As is, I'll probably mount the engine "inverted" with the carb pointing down, and exhausts up. I'll make some exhaust diverters from aluminum tubing or the like to direct the exhaust outward and back. Unfortunately I can't simply flip the exhausts on the G-Mark around because they're "keyed"....

Yep, that's the plan - or why bother building the model at all? ;)

The author did say that he had rounded the leading edge because the original airfoil was very sharp - do you think it needs more?

Oh, this is the type of Sunday Flyer I'm looking for, something to putter around the pea patch, and drag the wheels through the grass - I have other models to fulfill the other needs.

Although I would love to see others build this model, I couldn't give out or sell copies of the plans - the rights belong to the folks at See Temp (www.seetemp.com), and I especially wouldn't because of how well I was treated. Fred was kind enough to go out of his way to get a me copy of the plans the day before he left for his 3 week trip to the WRAMS show. Heck, he even sent the plans before he received payment from me! I hate to turn down a fellow modeler like this, but I hope you all understand. Drop Fred a line when he gets back from WRAMS and tell him Joe sent ya! ;)

Ooooops, my bad. I don't know what I was thinking! I agree, crystal clear colored coverings aren't for this model. However, the only covering experience I have is with the iron on plastics... there's a first time for everything I guess. On the other hand, I'm a looooong way from covering and scheme choices. ;)

There is progress though. Office Depot was able to make me a working copy of the plans for about $8 ($.49 / sq.ft.) which I'll use to make my templates from.... (This would make an awesome laser-cut kit!)

Thanks for all the support guys!

-Joe

RE: Avionnette HM-8 build thread.
 

I'd be against rep'ing the plans. They are available and the designer deserves to gain something for his efforts. Please just buy them from the supplier.

Joe, I saw the vid but it's an engine spinning a prop. It didn't indicate what the performance was.... or wasn't... :D You probably did say what it was doing but some nights I tend to flash over some of the posts just to move on to some other area. Life as a mod is tough.... All that responsibility to keep the WWW safe for wandering 1/2A'ers.... :D

RE: Avionnette HM-8 build thread.
 

What??? The second video I linked to shows the engine idling at about 5,000 RPM, and throttling decently up to about 13,300... ;)

But hey, I didn't come here to nit-pick, I just wanted to share some progress. It's been a little slow going.... OK, it's been a lot slow going, but hey, it's going. I'm really limited on space to work right now and am forced to work with an X-acto and straight edge - not too fun when working with lite ply (no power tools here). I'll most likely make the firewall out of 1/8" aircraft ply since I am going up with the engine weight and forces, but I think the rest of the airframe will be OK. A lot of the forward section is lite ply and should hold up well - the twin is a real smooth runner.

I'm debating on whether I should build a flat wing and add ailerons (as the original had) or just build it as a rudder-elevator model. :eek: Also, I think the G-Mark is a nice fit on the firewall, and if you look closely at the second picture, you can see the outline of the Cox reedie along with it's dummy cylinder. Funny how the G-Mark fits within those confines....

-Joe

RE: Avionnette HM-8 build thread.
 

Sorry Joe. I must plain missed the performace numbers. Some days I just flip through the posts as part of the mod duties rather than reading all the stuff in depth.

In these latest pictures the engine looks to be very inscale with the size of the model. I'm looking forward to seeing this one go and I'm going to order up a set of the plans for myself. Sadly in some eyes mine will have an electric motor hidden in the dummy twin. Or perhaps it's time to run in my own Gmark twin.

RE: Avionnette HM-8 build thread.
 

I was following this thread, nice looking aeroplane with some character. I saw an HM-8 drawing on fLea bay. it was the RC Modeller design together with a copy of the build article and an OS 10 R/C glow.

I won the bid in UK for £20.00 approx $42.00 seems a pretty good buy. I have three of the G-MARK flat twins, 2 NIB so the choice seems obvious.

I won't start for some time, just waiting to see how your build goes.



old git - - - - aka John L.

RE: Avionnette HM-8 build thread.
 

John, was this a fairly recent auction? Is there any chance you can post the item number? I'd just like to have a peek out of curiosity's sake... 42 USD does indeed sound like a pretty good deal - I woulda jumped on it, that's for sure! I hope you and Bruce do decide to build one, and of course power it with the Twins! Stick the OS .10 back on the Bay and recoup most (if not all) of your outlay! :)


There just so happens to be a little progress on the build... maybe it will entice ya'll to start a building frenzy!


-Joe

RE: Avionnette HM-8 build thread.
 

http://cgi.ebay.co.uk/ws/eBayISAPI.d...MEWN:IT&ih=014

What a struggle I have had to edit this and provide a link, now I know HOW to do it.

r/c model plan +engine LOOK ??? (330213172465)

Winning bid: £15.40
Ended: 28-Feb-08 20:47:53 GMT
Postage costs:
£3.99

It looks to me as if the structure NEEDS bracing wires. Mind you, nearly all my models are closely related to a brick built outhouse (with similar flying characteristics)

I still have a few years of RC Modeller, I couldn't believe that it had gone.


old git - - - - aka John L.

RE: Avionnette HM-8 build thread.
 

Thanks for the link, John. Sorry for the trouble, but as you say, at least now you know how to do it!

That's the same construction article that accompanies my plan, so yes, the design requires all of the bracing wires. It all looks intimidating at first, but once you dive in, it all starts making sense - it helps to have the article, but I don't think it's a necessity.

I plan on building the extended (50") wing model, and perhaps I'll add ailerons too. Although there's no published weight, I'm hoping to keep mine around 24-28 ounces - if it looks like it'll come out light, I'll add the ailerons.

Again, thanks for the link...

-Joe

RE: Avionnette HM-8 build thread.
 

Ailerons would be SO nice -- practicing forward slips with a plane like that might be all the entertainment I would need for a long time.

I saw See Temp's plans and a plane built from them at WRAM years ago -- almost bought them. The plane was so full of character and really attractive. Jim

RE: Avionnette HM-8 build thread.
 

Joe, I can't remember if I sent you a PM about the wire. Anyhow I've got it here. PM me your mailing address I can mail it to and there'll be an envelope of old .015 braided wire out for you soonest.

RE: Avionnette HM-8 build thread.
 

Joe, I just opened this thread for the first time. This is an awesome project. I'll stay tuned.

David

RE: Avionnette HM-8 build thread.
 

ProBroJoe, Wow, am I fortunate that I found this thread and that you're just starting your build. I purchased this plan about three years ago, but didn't think I had the skill to build it. I have that skill now, but this plan is pretty difficult to read. You mentioned that you received a copy of the article that went along with the plan. Would you be willing to sell me a copy. Maybe it will help me decipher this plan. I am not planning on putting an .049 into it. I am an all electric flyer land think a standard speed 400 might be able to fly this, if I can keep the weight down. I've tried to download some pictures from the internet, but they aren't very clear. There is a a nice full sized build located at
http://www.flyingflea.org/CanadianHM8/CanadianHM8.htm which may help me build this. Anyway, thanks for starting this thread. I will be waiting for each step you take in the build. Caley

RE: Avionnette HM-8 build thread.
 

Hi Joe, Got this picture over in my Forum. Shows a very nicely built HM.8 Caley

RE: Avionnette HM-8 build thread.
 

Wouldn't the plane be more 'stable' if it had some dihedral? That flat wing looks like it is 'drooping' on the ends. The partial view of the red-wing plane behind it appears that there is some dihedral in that wing. I understand that some folks build purely to the plans, and if the original called for 'flat', then the new wing must be flat.

RE: Avionnette HM-8 build thread.
 

For a purist and someone who is very good at flying radio control, yes, staying with the original would be best in my opinion. For someone like myself who needs all the help I can get when flying, I would probably put in about 1.5 inch of dihedral. All depends on what you are looking for in a model, authenticity or flyability. A note from a friend who is familiar with these airplanes. He mentioned that many people were killed trying to fly in the full sized ones, until the engineering fixed the problems. Heres another picture of another. Maybe one built in that era. Caley

RE: Avionnette HM-8 build thread.
 

I've read somewhere about their flying problems but the article was in french...

As I understood it, the problems where related to the leading edge (or other parts of the wing or the wing profile). In the original drawings this is rather sharp and that would limit the angle of attach. With a correct profile I can't see why it would fly well with no diheadral and ailerons.

There's also an ARF made by Hacker with plenty of diheadral and somehow it doesn't look that good...

RE: Avionnette HM-8 build thread.
 

Greetings from France! I'm here in an internet cafe in Paris killing a night before the Eurostar to London with connections to Dundee Scotland.

A week ago I was out to the French aviation and space museum at Le Bourget where they have an HM8 as well as a Pou on display. Pictures to come when I get home in another week and a half and figure out how to get the stuff out of the new camera.

The engine arrangement on that one is a touch different but I think there's pictures of the same one earlier in this thread.

RE: Avionnette HM-8 build thread.
 

Hi Bruce, your'e welcome to United Kingdom (irony) but really.

I went to Paris from Ebbsfleet via Eurostar last week, two hours to Gare du Nord. Came back the same evening, business is hell.

I had no time for sightseeing but loved what I saw of Paris. We went to Issy to look at an Incinerator.

I much prefer Eurostar to flying, much quicker and easier for baggage (I had none but I might have) for Paris anyway.

I'm looking forward to seeing your pictures of the HM. Have a nice trip.



old git - - - - aka John L.

RE: Avionnette HM-8 build thread.
 

Hello chaps, new here and so forgive me for dragging up an old thread but I was curious how the build went and whether the aeroplane flew?

I was doing some research on the full size aircraft when I came across this thread and it caught my eye because Ibuilt the model from the same plans many years ago when the plan was published. I exhibited the model at the International Model Engineering exhibition which in those days was held at Olympia in London. I picked up a commendation for the model. I still have it but it became a "Hangar Queen" as I took up full size flying and the models took a back seat. It now sits forlornly in my garage gathering dust, perhaps I should try and fly it one day! It was fitted with the Cox engine per plan.

On the question of dihedral Idiscovered during my research that the original full size Mignet machine had quite marked dihedral and this is shown in the early photographs and that it did NOT have ailerons but was flown by elevator and rudder alone. Ialso believe that Mignet largely taught himself to fly on this machine although Imay be wrong. The fact seems to be that his earlier creations were largely earthbound, except for the glider (HM5 I think) and were canibalised as each new design was constructed.

I believe a lot of accidents weren't the result necessarily of poor design but probably poor construction and / or piloting technique. There weren't the regulations in place that we have today and nobody was looking over the shoulder of builders to ensure that the construction was sound.

The plans from which this model were taken seem to be based on the layout of a machine built by a Mr Lerin I think who built , as far as Iknow, two machine, one in the 1930's and one in the 1980's. I think the later one is F-PYTU which is dispalyed in one of the French museums. Some of the machines have square edges to the main planes and some are rounded. For my money the HM8 is far more attractive than theHM14 flea.

Anyway, forgive the meandering.

RE: Avionnette HM-8 build thread.
 

The "Pou" 1933 or modern is by far the best looking, I have an Henri Mignet book from the mid 30's in my collection. The "Pou-du-ciel" was a home build but they had to be inspected before licencing,even back then the sky was already "controlled"!

RE: Avionnette HM-8 build thread.
 

Wow, this is weird - a coworker and I was just talking about this project on Friday - just moments before this thread reemerged!

Sadly, the model was never finished. I got as far as "making the kit" and gluing up the fuse sides, but there were a couple of concerns and the project lost momentum, and then was ultimately mothballed.

They say in life there are no coincidences, so I guess I better dig out the bits and get back at it!

RE: Avionnette HM-8 build thread.
 

NickR-J, I trust you realize that the Pou de Ciel and the HM-8 are two different planes?  The HM8 has very little or no dihedral and it does have ailerons.  It's the Pou that uses rudder and dihedral for turning and altering the angle of the forward wing for pitch changes.

RE: Avionnette HM-8 build thread.
 

Hi BMathews,

Yes I do know the Pou and the HM 8 are different. The latter being a forunner to the flea. The reason I said that the prototype HM8 didn't have ailerons and did have pronounced dihedral is because that is how it appears in a photograph of Mignet's original machine which I have in a book by Ken Ellis andGeoff Jones and the authors of that book (called Ibelieve"Henri Mignet and his flying Fleas"), Ihave the book but not in front of meas Iwrite, also say, if I remember correctly, that that is the configuration of the prototype HM8. The photograph was Ithink taken by Mignet's sister as she seemed to be behind the camera of most of the photographs of his various machines. As I understand it, later builders of the HM8 built it with flat wings and ailerons. I don't know if that is because the plans published were altered following the prototype. I believe it was Mignet's desire to make a machine that the man in the street could build and fly , that he was looking to simplify the concept of flying and went the pronounced dihedral, rudder/elevator only route. He managed to crash the prototype on a beach while flying it and it was that experience which led to the development of the flea. It may be that Mignet himself later incorporated ailerons into the design before he crashed it on the beach, Idon't know, the only photograph of Mignet's actual machine Iam aware of has no ailerons as far as I can see.

It's also worth noting I think that while the sky was "regulated" in the 30's as I understand it a lot of builders simply bought the plans and knocked up their own machines but didn't register them, many of the early photographs show machines, particularly in France, without any registration marks. I suspect the infrastucture for checking on homebuilds was not as careful in the 30's as it is now......and we are talking about France by the way, Isuspect there was a fair amount of laisse fair (forgive the spelling if it's wrong, I don't speak French, which is a shame because I'd love to be able to read the original plans!).

ProBroJoe it would be interesting to see if you do get it up and running. It's an interesting model. I might try and dig the images of mine out and scan them in but they were taken on film many years ago and Ihave a bit of trouble getting in to this site for some reason, once I'm in it keeps stalling when I want to go to different pages/threads etc. I'll see how it goes.

Nick

RE: Avionnette HM-8 build thread.
 

Checked the book last night, well I'm a little mystified now. On page 14 the author categorately states that the prototype HM8 was built without ailerons and was intended as a 2 axis machine as Mignet was looking to create a machine that the man in the street could build and fly. However, I looked very closely at the photograph of the machine in extremely good light and despite the very marked dihedral, it did have ailerons and for what it's worth a scalloped trailing edge......so there is the mystery, . Was it initially built as a two axis machine and altered later before the plans were published or did it have ailerons from inception. I guess we'll never really know, we do know that Mignet was an inveterate "tinkerer", he was forever building, rebuilding and so it's not beyond the bounds of possibility that he altered the machine. Certainly the amount of dihedral on the prototype would, I would have thought, made the machine less responsive to aileron inputs than the flat wing versions which appeared later. I think it is generally well accepted that Mignet was not a natural pilot, he clearly had trouble with three axis control while trying to learn under the guidance of his friend Pierre Colin on a conventional machine and so sought to complete his education himself on his own hand built machines. I suspect that as he was a low hours pilot,  still going through the learning curve was the cause of his crash on the beach in the HM8. I've seen two different accounts of what caused the crash but it would seem from what I've seen that an experienced flyer wouldn't have pranged the machine. Taking all that into account, coupled with the fact that from the information I have seen, most (may be none) of the original homebuilt HM8's were ever registered and some were certainly flown I think shows that aviation wasn't as strictly policed in 1930's France as it is today. Probably a good thing as it allows creation and development to flourish in my personal opinion, although I accept the need for regulation too for obvious reasons with our more crowded skies and more densely populated ground!

Sorry, wandered away from topic a bit but I find the HM8 rather interesting as I think it completely fulfilled Mignet's original concept:)

RE: Avionnette HM-8 build thread.
 

[img]file:///C:/Users/Home/Modellflug/Bilder/090902_Flugplatz/IMG_1371.JPG[/img][img]file:///C:/Users/Home/Modellflug/Bilder/090902_Flugplatz/IMG_1371.JPG[/img]Today I found the building thread of the HM-8 Avionette. I'm absolutely new in the RCU and from Germany. Two years ago I built the Avionette from Henri Mignets book "Comment j ai construit mon avionette". Its a wonderful plane and extremely rare. I built it from depron with a wingspan of 1,20 mtrs and a weight of 500 grms. Initially it should be a "quick & simple"-project. But Mignet chose solutions you could only build like Mignet. I wish the builder good luck with his HM-8 and hope, there are not to much mistakes in my text.

Hi ProBroJoe,
Where can I buy a set of those Plans?
Thank you,
Joe Pierson