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Author Topic: Another MAX-BEE ..... but ....  (Read 2995 times)

Online Massimo Rimoldi

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Another MAX-BEE ..... but ....
« on: March 08, 2018, 08:13:00 AM »

Hello to all
I apologize for my bad English but I hope you understand the same.

Some time ago I started to build a model using the composite wing and the Horizontal Stabilizer of Igor Burger's MAX-BEE.
I obviously asked Igor a copy of the plan of his model for the construction, but at this point I was presented with a small problem:
I wanted to use an I.C. engine in place of the Igor electric motor, but in the design there are at least two features that seem to be in contrast with this choice.

1) The nose of the MAX-BEE is very long and Igor uses the possibility of moving the batteries to get a correct trim
2) To counter-balance the gyroscopic effect that throws the nose up with right-handed propellers, the thrust line is very high, compared to the wing.

With the use of an I.C. engine all this would have caused the following problems:

1) The long nose would have required an extra ballast to correctly position the C.G.
The powertrain so forward would have led to an increase in the moment of inertia of about 20-25% compared to a conventional positioning, not counting the weight increase and the further increase in the moment of inertia due to the unavoidable ballast needed in tail.

2) In traditional stunt models with I.C. engine in inverted position (cylinder below) the C.G. is placed about 1" below the thrust line so, to position the wing according to the original drawings, I should have move the loadouts higher than about 0.6".
This operation, however, was impossible if I did not want to dissect the wing that had the loadouts already installed, alternatively I could ballast the landing gear to lower the C.G.

At this point I could not resist the temptation to keep the masses as close as possible to C.G. so I lowered the thrust line and shortened the nose, now I was no longer talking about the MAX-BEE but of a model that used its wing and its stabilizer.

Now I have a model that (at least for numbers) looks more like Igor's old Max and has lost the BEE.
Therefore, to complete the work, I decided to redesign the fuselage silhouette and inspire myself to the Spectre by Yves Fernandez.
The result is visible in the attached picture.

What are your ideas and how would you have faced the problem?
Your comments will be appreciated, Thank you.

Massimo

Offline Avaiojet

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Re: Another MAX-BEE ..... but ....
« Reply #1 on: March 08, 2018, 08:32:26 AM »
Massimo,

So you didn't use the foam Horizontal Stabilizer, correct?

Cb
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Online Massimo Rimoldi

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Re: Another MAX-BEE ..... but ....
« Reply #2 on: March 08, 2018, 08:39:52 AM »
No, all the horizontal parts are from Igor.
I only did the fuselage and the assembly

Online Brent Williams

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Re: Another MAX-BEE ..... but ....
« Reply #3 on: March 08, 2018, 01:55:57 PM »
Great looking plane! 
I hope it performs well also.

Laser-cut, "Ted Fancher Precision-Pro" Hard Point Handle Kits are available again.  PM for info.
https://stunthanger.com/smf/brent-williams'-fancher-handles-and-cl-parts/ted-fancher's-precision-pro-handle-kit-by-brent-williams-information/

Offline Tom Niebuhr

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Re: Another MAX-BEE ..... but ....
« Reply #4 on: March 08, 2018, 01:59:23 PM »
Beautiful !!!!!!! :)!
AMA 7544

Offline M. Scott

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Re: Another MAX-BEE ..... but ....
« Reply #5 on: March 08, 2018, 04:16:21 PM »
Very Nice!
Mike

Offline Skip Chernoff

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Re: Another MAX-BEE ..... but ....
« Reply #6 on: March 08, 2018, 04:25:40 PM »
Nice job!! Good Luck with it.

Offline Larry Fruits

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Re: Another MAX-BEE ..... but ....
« Reply #7 on: March 08, 2018, 09:09:09 PM »
Very nice indeed. Good luck with it.

 Larry

Offline Lauri Malila

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Re: Another MAX-BEE ..... but ....
« Reply #8 on: March 08, 2018, 11:47:17 PM »
Nice model, Massimo.

I have a similar project, just progressing quite slowly.
To me Igor advised to keep the original nose lenght, even if it means that I must add lead to tail to balance the thing. Maybe Igor can explain why..? Luckily my engine is very light.
Lauri

Offline Brian Gardner

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Re: Another MAX-BEE ..... but ....
« Reply #9 on: March 09, 2018, 12:41:53 AM »
Looks great mate

Offline pmackenzie

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Re: Another MAX-BEE ..... but ....
« Reply #10 on: March 09, 2018, 04:41:58 AM »
Nice model, Massimo.

I have a similar project, just progressing quite slowly.
To me Igor advised to keep the original nose lenght, even if it means that I must add lead to tail to balance the thing. Maybe Igor can explain why..? Luckily my engine is very light.
Lauri


Pretty sure the nose length is there to get the desired distribution of lateral area.

Pat MacKenzie
MAAC 8177

Online Massimo Rimoldi

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Re: Another MAX-BEE ..... but ....
« Reply #11 on: March 09, 2018, 05:25:28 AM »
For everyone:
Thank you for the appreciations about the look.
I hope that it will fly well, unfortunately they did not send me the pilot when they shipped the fiberglass parts so I will try to do what I can.

For Lauri:
I hope your project is faster than mine, I cut the first piece of balsa in September 2016 ....
Yes, I read an Igor article on SN  in which Igor says that the long nose helps in the wind.
Unfortunately my poor knowledge of English and my few rudiments of aerodynamics did not help me to understand completely.
I hope someone here will help me to resolve my doubts.


Massimo

Online Massimo Rimoldi

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Re: Another MAX-BEE ..... but ....
« Reply #12 on: March 09, 2018, 05:26:59 AM »

Pretty sure the nose length is there to get the desired distribution of lateral area.

Pat MacKenzie

Hi Pat
Yes, the problem is without a doubt the side area.
Unfortunately I think I understand that Igor says that a longer nose  increases the tension of the linees when the wind blows
in your face.
This contradicts what I believe.
They are instead in favor of the longer nose (more lateral surface in front of the GC) because it reduces the tendency to pitch during the flight in the wind.

Massimo
« Last Edit: March 09, 2018, 06:34:26 AM by Massimo Rimoldi »

Offline Don Jenkins

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Re: Another MAX-BEE ..... but ....
« Reply #13 on: March 09, 2018, 05:46:10 AM »
Outstanding!  Really like the open cockpit and color scheme!  Nicely done!!

Don

Offline Vitalis Pilkionis

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Re: Another MAX-BEE ..... but ....
« Reply #14 on: March 09, 2018, 08:39:54 AM »
Very beautiful airplane, Massimo. By the way, check out the Max60 with which R.Kornmayer won WC in 2011. It did not have such a long nose, but was a decent stunt machine.
From personal experience I can tell that is almost impossible to have a CG of electric model with Axi2826 at the right place, even with 6S battery at the very front, if the nose is shorter than 300mm (as in Igors Maxbee).
So that long nose really is a necessity with this kind of setup.

Offline TDM

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Re: Another MAX-BEE ..... but ....
« Reply #15 on: March 09, 2018, 09:31:46 AM »
Massimo I do not see anything wrong with what you did. Very beautiful model indeed. For sure it will be awesome in the air.

IC weight distribution tends to move forward because the motor is the heaviest component at around 12oz or so with fuel tank behind at 6oz. The Electric models are quite different with the lighter motor in the front 6.8-7oz motor and the heavier battery behind it, in addition to that a purposely Electric built model doesn't need the heavy duty anti vibration built a IC nose requires so you can say the front structure gets or can get even lighter.  This alone leads to a longer nose to balance things out", you go with a very light tail or both.

Each goal you meet is a moment of happiness
Happiness is the harmony between what you think and what you do. Mahatma Gandhi

Online Igor Burger

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Re: Another MAX-BEE ..... but ....
« Reply #16 on: April 02, 2018, 02:13:50 PM »
Hi Pat
Yes, the problem is without a doubt the side area.
Unfortunately I think I understand that Igor says that a longer nose  increases the tension of the linees when the wind blows
in your face.
This contradicts what I believe.
They are instead in favor of the longer nose (more lateral surface in front of the GC) because it reduces the tendency to pitch during the flight in the wind.

Hi Massimo, little later, but better later than never :- )) Nice looking model :- ))

Yes, Pat is right, the side area is for proper (low) yaw stability of fuselage and it was target, not accidental solution. I had long nose on predecessor of Max Bee as you pointed, it was Max and Max II. It had Os Max .46 with pipe in nose so it was easy to keep long nose.

Mentioned Max 60 which was developed especially for Richie K. had shorter nose, because target of his daddy (Richie was kid that time) was usage of ST60 and it was really heavy engine and I did not find solution with longer nose. However later it was model used lot in Europe, for example Alex Schrek placed always very high with it (he used little modified fuselage shapes, but aerodynamically identical). However Max 60 was without logarithmic flap unit. So for strong hands.

Reason for long nose is not increasing of line tension against wind, it is to make stable position with side wind. Simply fuselage of Max Bee is designed to keep constant yaw independent on side wind and thus to be in good trim also in wind and turbulence (we know how essential is position of leadouts and of wind yaws model, whole trim is lost). Just some days ago we spoke about it in Rabe rudder thread here on SH.

Here is link to page with max II:
http://www.netax.sk/hexoft/stunt/the_max_ii.htm


Online Massimo Rimoldi

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Re: Another MAX-BEE ..... but ....
« Reply #17 on: April 03, 2018, 12:46:51 AM »
Hi Igor, thanks for the reply.
Yes, I have followed your speeches in the last days.

Regards, Massimo


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