Logo
Builders' Plan Gallery  |  Hip Pocket Web Site  |  Contact Forum Admin  |  Contact Global Moderator
October 20, 2017, 10:58:38 PM *
Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with email, password and session length
 
Home Help Search Login Register
Pages: [1]   Go Down
Print
Author Topic: HM 293  (Read 1344 times)
0 Members and 1 Guest are viewing this topic.
sprogs
Silver Member
****

Kudos: 6
Offline Offline

United Kingdom United Kingdom

Posts: 202


Topic starter


Ignore
« on: September 19, 2017, 01:55:48 PM »

I would like to build a model VERY loosely based on Henri Mignet's HM 293.
I have a 3v of it and it seems to have an almost symmetrical section on both wings and BOTH wings seem to have positive incidence.
Is this true? Why does it seem wrong to me?
Does anyone out there have any idea of where my thinking is wrong? Please ?
Liz
P.S. I've tried three times to attach a 3v of it but I must be doing something wrong.
Attached files Thumbnail(s):
HM 293
Logged

The interface between air and ground has no thickness at all. So why do I always find room for my aircraft there ?
steveair2
Silver Member
****

Kudos: 4
Offline Offline

United States United States

Posts: 185



Ignore
« Reply #1 on: September 19, 2017, 02:27:34 PM »

Liz,  the front wing on the full scale 293 pivoted changing the incidence of the wing.  It was hinged at the front spar.  The wing pivoted with fore and aft movement of the joystick.  That three view may not represent flight attitude incidence.
Logged
sprogs
Silver Member
****

Kudos: 6
Offline Offline

United Kingdom United Kingdom

Posts: 202


Topic starter


Ignore
« Reply #2 on: September 19, 2017, 02:38:09 PM »

Thanks Steve
I understand that the hinge on the front wing was arranged so that there was always a slight pull on the control column. If I remember rightly if the front wing's incidence became greater than about 15 degrees, interaction would cause it to be unable to return. It's just that the rear wing seems on the 3v's I've seen to be +ve.
Can you have both wings +ve and still be stable?
I have two foam core wings identical except for span that I would like to use, they are symmetrical section and I just wondered.........
Liz
Logged

The interface between air and ground has no thickness at all. So why do I always find room for my aircraft there ?
steveair2
Silver Member
****

Kudos: 4
Offline Offline

United States United States

Posts: 185



Ignore
« Reply #3 on: September 19, 2017, 03:01:42 PM »

I don't know enough about the 293 or tandem wings to answer.   I'd try to find the recommended CG from a model or full scale 293.
Then do some test glides with a cheap balsa glider.
Logged
ZK-AUD
Gold Member
*****

Kudos: 21
Offline Offline

New Zealand New Zealand

Posts: 747



Ignore
« Reply #4 on: September 19, 2017, 03:12:07 PM »

I think the issue you were talking about was with the HM14 - the original flea.  There was insufficient gap between the front and rear wings.  If you got into a steep enough dive with sufficient airspeed the slot effect between the 2 wings created additional lift on the rear wing pitching the nose down.  When you hauled back on the stick this made the problem worse and therefore it was unrecoverable.  3 or 4 fatal crashes occurred and at least 1 was seen to go into the ground inverted. The flea was modified by stretching the fuselage and raising the top wing to increase the gap.  There was also a mechanical linkage added to the rear wing to pump on some negative incidence as the T.E. of the front wing came down. 

I hadn't heard that there were any lingering issues with the 293 however.  I have quite a bit of information on Mignet's Fleas including full size plans for various models sitting at home if you need anything .  Some very modern versions are still produced and I believe fly under the French ULM certification
Logged
sprogs
Silver Member
****

Kudos: 6
Offline Offline

United Kingdom United Kingdom

Posts: 202


Topic starter


Ignore
« Reply #5 on: September 20, 2017, 12:24:51 PM »

Dear ZK - AUD
I love, and have always loved Henri Mignet's designs. If there is any information you would care to share or any plans you might care to sell I would be both interested and grateful.
Liz
P.S.
I have an original copy of "The flying flea" by Henri Mignet. it's signed I believe in French dated 1937.I cannot read the name. It appears to be a first edition by The Air League of the British Empire. If it would be of value to you to swap for information or plans or such I would be very interested.!
Logged

The interface between air and ground has no thickness at all. So why do I always find room for my aircraft there ?
ZK-AUD
Gold Member
*****

Kudos: 21
Offline Offline

New Zealand New Zealand

Posts: 747



Ignore
« Reply #6 on: September 20, 2017, 02:16:17 PM »

Liz,  I'll see what I have on the 293 and just scan it for you.  If you want to send me a PM with an email address that would work

Regards,  Mike
Logged
Big G
Bronze Member
***

Kudos: 1
Offline Offline

United Kingdom United Kingdom

Posts: 72



Ignore
« Reply #7 on: September 21, 2017, 07:35:45 AM »

You doubtless know this already, but if you feel the need to examine a full-size Pou, there's one on display at RAF Cosford Museum.

G
Logged
Tapio Linkosalo
Platinum Member
******

Kudos: 27
Offline Offline

Finland Finland

Posts: 1,086



Ignore
« Reply #8 on: September 21, 2017, 08:07:20 AM »

.Can you have both wings +ve and still be stable?

Sure. Consider modern FF models, that have a few degrees of incidence (power models and catapult gliders even less), and still are stable. They all glide with wings 5 to 7 degrees AoA, so the tailplane is also on positive angle. It all comes down to tail volume (tailplane area * tail moment) and location of the CG. With large enough tail volume and at CG, the setup can be stable even with both lifting surfaces on positive angle. The Flea has a large tailplane. Also the Flea has short moment, so the aft wing lies in the wake of the front wing which bends the airflow down. Thus the aerodynamic AoA of the aft wing is actually less than the geometric.
Logged
sprogs
Silver Member
****

Kudos: 6
Offline Offline

United Kingdom United Kingdom

Posts: 202


Topic starter


Ignore
« Reply #9 on: September 21, 2017, 01:30:48 PM »

Thanks Tapio
I think I get the hang of what you're saying, but if you could direct me to some more (preferably not too technical information I would indeed be grateful).
Liz
Logged

The interface between air and ground has no thickness at all. So why do I always find room for my aircraft there ?
ZK-AUD
Gold Member
*****

Kudos: 21
Offline Offline

New Zealand New Zealand

Posts: 747



Ignore
« Reply #10 on: September 22, 2017, 06:00:17 AM »

the full size plans for the 293 specify +6 degrees on the rear wing.  My instincts say this relates to the very short moment and is necessary to keep its bum up!  the front wing pivots from 0 to +12 and I think I read that it cruises at +3.
there's an old rubber model I posted on Outerzone called Skeeta.  have a look and you'll see it has positive incidence on both wing and tail thus building in downthrust



Logged
Tapio Linkosalo
Platinum Member
******

Kudos: 27
Offline Offline

Finland Finland

Posts: 1,086



Ignore
« Reply #11 on: September 22, 2017, 07:28:32 AM »

I think I get the hang of what you're saying, but if you could direct me to some more (preferably not too technical information I would indeed be grateful).

Uh. I'd recommend "model aircraft aerodynamics" by Martin Simmons, but I'm afraid that it somewhat falls under the "technical" definition. The issue of longitudinal trim and stability tends to be rather complex, so I'm afraid there are no too simple solutions. But then again, one does not need to have a degree on aerodynamics to follow Simmons' text. Try that!
Logged
malc
Silver Member
****

Kudos: 12
Offline Offline

United Kingdom United Kingdom

Posts: 190



Ignore
« Reply #12 on: September 22, 2017, 10:10:18 AM »

There is a Peanut plan by Walt Mooney called Lederlin 380L flying flea published in model builder January 1977, which could be a good starting point for wing incidence - all mooney plans I have built have flown well.

Shonai Peanut build blog - you may have to use the translate feature of your browser.
http://blog.goo.ne.jp/jiroaerop2014/e/a3a7f7fc4ea65e3ac0d32f6b7d8a3a67

Malc.
Logged
PB_guy
Gold Member
*****

Kudos: 6
Offline Offline

Canada Canada

Posts: 381


Just a kid at heart.



Ignore
« Reply #13 on: September 22, 2017, 06:27:31 PM »

I have that peanut plan by Walt Mooney and the article. If anyone wants a copy then send me a PM with an email address.
ian
Logged
sprogs
Silver Member
****

Kudos: 6
Offline Offline

United Kingdom United Kingdom

Posts: 202


Topic starter


Ignore
« Reply #14 on: September 25, 2017, 01:28:08 PM »

Thank you Ian
I look forward to showing you the end results. (Emphasis on "The End") I know I should have more confidence in myself.
Liz
Logged

The interface between air and ground has no thickness at all. So why do I always find room for my aircraft there ?
cavelamb
Silver Member
****

Kudos: 7
Offline Offline

United States United States

Posts: 204


yup!

WWW

Ignore
« Reply #15 on: September 25, 2017, 11:07:00 PM »

Thanks for the HM-3880 plan, Ian.

I was looking at it thinking I might could draw the 293 from that.
Someday...
at the moment I'm moving and everything is hidden in boxes.
Logged
PB_guy
Gold Member
*****

Kudos: 6
Offline Offline

Canada Canada

Posts: 381


Just a kid at heart.



Ignore
« Reply #16 on: September 26, 2017, 03:05:25 AM »

You are both welcome. I remember when I first got the magazine in '77 and thought about building it, but it seemed too complex for me at the time. Every once in a while, I go through my model magazine collection to get some inspiration.
ian
Logged
Big G
Bronze Member
***

Kudos: 1
Offline Offline

United Kingdom United Kingdom

Posts: 72



Ignore
« Reply #17 on: September 26, 2017, 04:51:31 AM »

If it's any help there was a plan article for a 44" Flea in December 1963 Aeromodeller, by Fred Longbon. This was the UK-made Carden-Baynes version. The model used a DC Spitfire diesel (1 cc?). Full-size plan available on Outerzone.


G
Logged
billdennis747
Titanium Member
*******

Kudos: 36
Offline Offline

United Kingdom United Kingdom

Posts: 2,677



Ignore
« Reply #18 on: September 26, 2017, 11:12:44 AM »

If it's any help there was a plan article for a 44" Flea in December 1963 Aeromodeller, by Fred Longbon. This was the UK-made Carden-Baynes version. The model used a DC Spitfire diesel (1 cc?). Full-size plan available on Outerzone.
G
I was there at Old Warden, maybe early 70s and saw Fred's Flea fly (try saying that fast). Guess what; it tucked under and crashed.
Logged
RalphS
Gold Member
*****

Kudos: 17
Offline Offline

United Kingdom United Kingdom

Posts: 635



Ignore
« Reply #19 on: September 26, 2017, 02:38:59 PM »

I was halfway through designing a Flying Flea for CO2 in, I think, 1982 when the Aeromodeller arrived and it had a plan for a Flea similarly powered.  I made the Aeromodeller version and it flew very well.  There was a full size one in the Newark Air Museum.
Attached files Thumbnail(s):
Re: HM 293
Logged
ZK-AUD
Gold Member
*****

Kudos: 21
Offline Offline

New Zealand New Zealand

Posts: 747



Ignore
« Reply #20 on: September 26, 2017, 07:04:30 PM »

Hi all - I was able to help Liz out with a full set of construction drawings to build a real HM293.  I have since posted it in the plans gallery - this is the definitive stuff fully detailed with all parts and fittings - you could draw a perfect scale plan from this   
Logged
Big G
Bronze Member
***

Kudos: 1
Offline Offline

United Kingdom United Kingdom

Posts: 72



Ignore
« Reply #21 on: September 27, 2017, 03:48:16 AM »

If it's any help there was a plan article for a 44" Flea in December 1963 Aeromodeller, by Fred Longbon. This was the UK-made Carden-Baynes version. The model used a DC Spitfire diesel (1 cc?). Full-size plan available on Outerzone.
G
I was there at Old Warden, maybe early 70s and saw Fred's Flea fly (try saying that fast). Guess what; it tucked under and crashed.

Well, what a surprise!

G
Logged
Pages: [1]   Go Up
Print
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.21 | SMF © 2015, Simple Machines Valid XHTML 1.0! Valid CSS!