# Hi, from Colombia

Discussion in 'New Member Introductions' started by Eduardo Fadul, Jan 13, 2011.

1. Apr 9, 2011

### Eduardo Fadul

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Hi all

i like this idea, with the high tail is really possbile, but +/- what is the price of this jet engine??? may be for the tigrillo 2.0

This is a normal concern here too, we only have several hirth in the country however i have hear good comments about it; at the beginning of this design when i was talking with the pilots them request no rotax, not for performance, for the \$ of their maintenance. I'm considering have 2 engine configurations, the HKS 700E looks interesting :think:

You get with the achilles' heel of this plane. The pilot should be +/- 80 Kg (175 lb), also a heavier pilot is a wider pilot and the plane is 60 cm wide, so this will limítate the amount of pilots that could fly in this plane :ermm:

2. Apr 9, 2011

### harrisonaero

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For this type of plane, the HKS engine seems a natural and is worth serious consideration during this stage of your design.

With religious maintenance, the Rotax two-strokes seem to do OK for draggy airplanes but for slick planes it's just too easy to unload the prop during a descent and cause a lean mixture and seized engine.

And I'm not a 2-stroke hater either, I've come out and learned to embrace my engine-uality in all it's forms. I've even been known to been seen in public with my two-stroke chainsaws, motorcycles, and snowmobiles And once I even owned a, gasp, r*tary engine...

3. Apr 9, 2011

### Autodidact

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Hey Eduardo, are you going to attach the tail booms to the front spars also?

4. Apr 9, 2011

### autoreply

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5000-10K EUR for the model ones, AMT jets for example. No idea about TBO and maintenance, but given their modeling background, I guess they're high and low.
Make sure you have provisions for 2 battery-tie-downs, one in the nose and one as far aft as possible. Shifting them can give you something like a 60-85 kg range with the battery in the nose and 75-100 kg with the battery in the back, at least, that's how glider pilots do it.

5. Apr 9, 2011

### Eduardo Fadul

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Yes sir, i'm thinking in a socket that will receibe the booms and be next to the bellcrank for the control rods, something like this

6. Apr 9, 2011

### Eduardo Fadul

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I only was thinking in one battery as aft as possible, but i'll keep in mind your idea

best regards

7. Apr 12, 2011

### Yogi

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You skinny guys are sick! Just wait about 20 yrs. and you will wish you had designed for a 220 lb. pilot !! Yogi

8. Apr 12, 2011

### JMillar

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Ah, at 24 I'm at 120lbs - but I know that my brother is 20lbs heavier and almost 20 years older. Dad is another 25 or so years past him, and another 15 lbs. But I'm vegan, and they're not, plus they already weighed about that at my age. So I feel confident that I'll be able to fit into the KR2 I want to build. My girlfriend of 8 years weighs less.

9. Apr 12, 2011

### Eduardo Fadul

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You're complete right, the planes MUST be for everyone; this is not our hobby, this is our love even our life

I just have a little problem, , i dont have money for something bigger, so i must make the biggest safety plane that i could, this is how this plane born.

Best regards

10. Apr 12, 2011

### Sacha

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Hi Eduardo, Like the looks of your plane, but in your structural drawing I wonder why the Booms (pods? don't know how you call that in english) don't reach to the main spar. Seems pretty essential to me.
I also was thinking if it wouldn't be relatively easy to design the wingtips (from the booms till tips) to be detachable, so the plane would be easier to hangar/trailer.
I would like to follow your design proces, especially because I hope I could learn a bit from this. It seems like you know what you are talking about so to speak. (excuse my english)
Thanks in advance!

11. Apr 12, 2011

### Sacha

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Ooops!
I missed the second page! So this question is out of date!

12. Apr 14, 2011

### Eduardo Fadul

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Hi Sacha

The idea of use the winglets is not discarted at all, i know the wing loads but i must calculate the loads that a small winglet will create onder:

about the handling, the ideal is that the plane should be easy to disarm into 3 main components, a two men work of +/- 15 minutes, fuselage + tail boom + wings, something like this (an unsuccessfully uav design for our air force :depressed )

Best Regards

Last edited: Apr 14, 2011
13. Apr 14, 2011

### Eduardo Fadul

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I have a question for those that know about sailplane

I want a one pice cockpit like in the sailplanes, but acorting to this plane's MEL (Minimum equipment list) a parachute will be obligatory, so is there any sailplane with parachute that open the canopy forward???? i have the concern that this configuration will be dangerous at the (god help us) event that the pilot must leave the plane

if the canopy open aft the same wind will help us to open it and keep it far from the pilot, that is why i have to cut the canopy into two pieces :ermm:

14. Apr 14, 2011

### topspeed100

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We have a saying in Finland...anyone under 100 kg are being measured at the nursery.

I have similar design too ( sketch )...but there is lotsa sweep in the wing ...that way the weight distribution is less critical.

15. Apr 14, 2011

### autoreply

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Winglets are pretty hard to design aerodynamically and I guess that's the reason you don't see them that often. If you simply bolt on a vertical airfoil you'll get pretty horrible results.

I really like the upswept tips (Ventus 2B/C and Discus 2 have them) and they're a lot easier to design for, with pretty good results in lower induced drag.
Virtually all of them. They have a release such that the whole canopy hinge is let go off when you have to jump. You better have Roeger-hooks, otherwise the canopy will hit your face.
From hear-say; those kind of canopies often break to the side (if you're spinning), cutting the throat/head of the pilot. Also I really wouldn't like the risk of the canopy opening during flight. That sometimes happens and in this case it's a pretty serious event.

16. Apr 15, 2011

### Eduardo Fadul

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topspeed100 the problem with the sweep wing is the stall speed, you need a larger area to reach and/or heavier (a more complicated flaps or slats) wing to get the same Vs :ermm:

ps: I really desire to see your plane in the sky
ps2: In colombia a 100 Kg person is a big one, our race is +/- 1.7m (5.57 ft) tall so the normal weight is about 80-90 Kg (176-198 lb), i'm 6ft tall and 75 Kg (165 lb)

An upswept tip, relative more easy and the same good results; anyway is this plane them are more aesthetical than functional.

Really dont kown about it, never hear that, could you please explain me (and teach me) what is that and how does it works???? if you have pictures/schemes even better

this is right too, i'm thinking in a steel structure to avoid the canopy's bend

To avoid unwanted openings i wish a system like the one in the A-37B Dragonfly

If the locks are at the canopy the idea is block it with a bar in side the cockpit
If the locks are at the cockpit the should rotate to wrap a bar in the canopy

However to be complete honest i really really wish a one-piece fwd opening canopy.

Best regards

Last edited: Apr 15, 2011
17. Apr 15, 2011

### autoreply

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They're fully functional. In fact a wing with the frontal look of a half-ellipse and the top-down look of an ellipse is the most efficient one and both the Dreamliner and A350 are going that route.
The problem with winglets is that they're quite sensitive to slip and it's not easy to design them with enough tolerance to it and still have a measurable gain. Tips with about 20 degrees dihedral don't have that problem and they're yaw-stabilizing.
DG-Flugzeugbau.de : Roeger Hook
The problem usually isn't the latching mechanism, but the pilot, who forgets to close it, or accidentally opens it in flight. A forward-hinged one will open only a bit, a rear-hinged one will break loose and smack you in the face, most side-hinged ones will simply open and stay there. Another problem with the rear-hinged one is that you easily damage it during entry, I've almost done so myself to a club Libelle.

Googling around will give you a lot of ideas for hinging mechanisms and the like. My preference would be a front-hinged one with Roeger-hooks, but that's probably 5 lbs or so heavier than the other options, though it's a lot easier to fit into the canopy frame.

18. Apr 15, 2011

### Yogi

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Eduardo (Skinny), Have you considered any of the ballistic chutes available (if thats an option)? BTW I think you have one sweeeet design there. I also think a lot of us have drawn something like that on a napkin when we were dreaming stuff up. You are realizing a lot of peoples collective dreams. Thanks and I hope you keep it up. Yogi

19. Apr 17, 2011

### Eduardo Fadul

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Big Yogi, you really make me laugh.

You ruin the surprise :. I was thinking in the BRS 600 Canister, i wrote some time ago to the company to get info about how install the system and what are the requirements. I was thinking in both systems and that the final user choose which one preffer, but my election is the ballistic for obvious reasons

But i dont know if BRS Aerospace is still in the Business because their page says 2009 onder:

Best regards

20. Apr 17, 2011

### Eduardo Fadul

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Big Yogi, I'm in the moment in which I can modify the aircraft, so let me see if i can enlarge the plane (wings and more tails arm, maybe 2 extra ft for the fuselage to compensate the CG) a little bit to accommodate a bigger pilot, but please tell me what are the measures for a regular big pilot, can you fit in a 60cm (2 ft) wide cockpit?