Yuu

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.

EDFFanatic

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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

Mr Cox

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...

BMatthews

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.

old git

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.

NickR-J

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.

coriolan

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"!

ProBroJoe

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!

BMatthews

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.

NickR-J

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

NickR-J

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

Pouduciel74

[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.

Joe Pierson

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