big 3 meter twin boom pusher just crashed

[red_gol]

We did the first test last weekend.

It doesn't have aileron. It's powered by a 26cc gas engine.

The plane turned to right after left the ground. And crashed after 3 seconds in the air.

Two carbon fiber boom pipes broken. But the fuselage and the main wing weren't hurt. The alveolate(beehive?) construction is really tough.


Winspan: 3 meters

Due to the heavy tail, we put a 3kg weight in the nose to make a right CG.


Do anybody have experience with eject launch? Or a net landing?

[_helitron_]

Hi,

sorry for this mistake :( ! Can't help you in the moment but since last year I'm also working on a Aerosonde klon:

http://www.rclineforum.de/forum/thread.php?threadid=139288&sid=

Had til today no luck to find a real Aerosonde-like fuselage. Is your fuselage a selfmade one and only one piece for this project or is it eventually possible to buy such a fuselage ?

Thanks for answer and good luck for the next try :) !

As you can see on the attached photo I'm a great fan of the Aerosonde :D !

Best wishes,

Erwin

[Sail-r]

red_gol;

Sent you a PM.
Bryan

[rcdoma]

Sorry to hear about the crash on your maiden flight. That's a nice looking bird, hope the second flight goes smoothly. I saw a buddy use this: http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXE635&P=0 to get his 2m, 4.5Kg electric pusher UAV in the air. He was using an AXI 2800 series motor in it and belly landed it on a grassy strech beside the runway.

The heavy duty Hi-Start might work for you -has anyone tried it?

[Unterhausen]

Sounds like there may be problems with the stability of that plane. Also the thrust angle may not be enough given the small amount of dihedral.

Either that, or it wasn't going fast enough. We had problems with our plane getting up to speed on long grass.

I think people usually use bungee launchers for a reason. I'm no expert, but the hi-start launches I've seen look like they would be pretty exciting on anything other than a glider

[clolson]

I'm not an aerospace engineer, but I'll still happily make my own comments and observations.

My main concern is your statment that you have no ailerons on this otherwise beautiful aircraft. With no ailerons you will need a fair amount of dihedral for effective stability and control. From your pictures, I'm not sure you have enough. (?) In addition, I wonder if your a-frame tail design will give you enough rudder authority to effectively command a no-aileron aircraft?

In my personal experience with no-aileron aircraft, you have to be very careful with any kind of cross wind. You can't directly control the bank angle of your aircraft, so if you catch a cross wind gust that lifts a wing, the best you can do is kick in rudder to compensate ... but the aircraft bank angle reacts very slowly because the rudder takes time to yaw the airplane, and then the lift differential/dihedral takes time to move the wings back towards level. It's very easy for a gust to raise a wing tip, put you in an odd attitude, and close to the ground you can catch the opposite wing tip on the ground and your flight times become very short.

Up in the air, you have the same issues, but you have much more time to react so it's not nearly as big of a problem. Your approach and landing can be interesting though for the same reasons. Gusts can knock you off level and force an unwanted turn, but with rudder only heading control, it takes significantly longer to correct for this and level the airplane or turn it back in the direction you want to go.

So with no ailerons on your design, you probably need more dihedral, it probably wouldn't hurt to have a more conventional tail with better control authority at least in rudder, you want to avoid any kind of cross winds until you get really comfortable and confident controlling the aircraft, and any rudder input you use to help level the wings is going to react *much* slower than an aircraft with ailerons, so you really have to think a lot further ahead, and be really sharp and quick on the controls.

That's just my $0.02 ... I've been flying R/C airplanes since high school, but my degree is in computer science, so I speak with some small bit of practical experience, but not a lot of solid aerospace theory to back that up.

I don't mean this as a nit-picky message, your aircraft really looks beautiful.

Regards,

Curt.

[Munin]

Hello Red

What a beauty you got there. Good craftmanship I see.
If you dont mind me asking what wing profile are you using
and gross weight ?

Keep the spirit up, after failure comes success.

/Munin

[Unterhausen]

It's really hard to judge from the pictures, but it almost looks like the tail has a positive incidence relative to the wing. You don't want to have a flying tail in this configuration. I am also working on a plane with a v-tail, pusher, and rudder steering configuration, although I'm sure mine will not look as nice. My wing came off of another plane, so I'm sure it has enough dihedral.

[XJet]

clolson is correct -- this design appears to have very little dihedral so there will be only minimal roll coupling with rudder application.

What's worse, with the anhedral tailplane, there may even be a slight *reverse* roll coupling when rudder is applied, causing the plane to tend to roll the *wrong* way in response to rudder inputs.

I would certainly consider increasing the dihedral or adding some ailerons and providing some aileron/rudder coupling so as to improve the turning characteristics.

[Unterhausen]

rudder on this plane puts a torque that tends to bank the plane in the direction you want to turn, so I think that's ok. Unless my hands are flying upside down or something.

[red_gol]

Your comments and encouragement are so helpful that I feel confident to try it again.

We just cut the ailerons on the wing and changed the engine from 26cc to a DA50.

[rjfon1]

G'Day red gol.
Sorry to hear about the incident.
Seeing that you have put a DA50 on the aircraft, you could consider putting a constant speed prop on it. Have a look at
http://www.variablepitchhobbies.com/
They have a unit on a DA100 on an Extra I think, with a weight of 31lbs, and hovers!!!
A this stage it's only available on a DA100, but I thinks the DA50 was in the works.
What's more, it can be put into beta and reverse, which I think would be a bonus with the type of operations an AUV can be involved in.
Regards,
Rob.
Melbourne Australia.

[red_gol]

Hi,

sorry for this mistake :( ! Can't help you in the moment but since last year I'm also working on a Aerosonde klon:

http://www.rclineforum.de/forum/thread.php?threadid=139288&sid=

Had til today no luck to find a real Aerosonde-like fuselage. Is your fuselage a selfmade one and only one piece for this project or is it eventually possible to buy such a fuselage ?

Thanks for answer and good luck for the next try :) !

As you can see on the attached photo I'm a great fan of the Aerosonde :D !

Best wishes,

Erwin

Erwin,

This plane was made by a local factory in China. It is not cheap, but if you like we can talk.

BTW, I cannot understand the language on your website, and it requires an account to view.

Cheers,

Alex

[_helitron_]

Erwin,

This plane was made by a local factory in China. It is not cheap, but if you like we can talk.

BTW, I cannot understand the language on your website, and it requires an account to view.

Cheers,

Alex

Hi red_gol,

thanks for answer !

I guess you mean the whole plane above, is it so ? Actually I'm interested in the fuselage because I've got already the wings from a glassfiber glider with ailerons and flaps. But nevertheless I'm curious about the costs of the whole plane and when available of the fuselage alone.

Ok, sorry, the website is written in german, but I'd more to indicate to the pictures there but forgot unfortunately to mention the registration :o . On the pics there are to see the glider wings for my Aerosonde clone I've mentioned above. But have attached now a pic here of the wings.

Btw. regarding your accident with your plane I'm also pretty sure you need absolutely ailerons for such a plane and in my opinion flaps also for landing (or flaperons, that means both ailerons a bit down or up). Don't know if you did it already but please check once this Aerosonde construction site

http://www.ctie.monash.edu/hargrave/hargrave_150.html

respectively look more precisely for the wing construction.

I saw that you've build ailerons in the meantime on your wings, that's very good for sure :) .

Again good luck for the next try !

Cheers, Erwin

[red_gol]

G'Day red gol.
Sorry to hear about the incident.
Seeing that you have put a DA50 on the aircraft, you could consider putting a constant speed prop on it. Have a look at
http://www.variablepitchhobbies.com/
They have a unit on a DA100 on an Extra I think, with a weight of 31lbs, and hovers!!!
A this stage it's only available on a DA100, but I thinks the DA50 was in the works.
What's more, it can be put into beta and reverse, which I think would be a bonus with the type of operations an AUV can be involved in.
Regards,
Rob.
Melbourne Australia.

Rob,

Thanks. But I wasn't able to enter the site from China. I guess it must be very cool. Don't know how complicated it is. And is it heavy?

Cheers,

Alex

[John O'Sullivan]

The airplane is a well proportioned and efficient design. However, a model of these proportions will not operate without ailerons. Get them working and you will have a very efficient (and controllable) model
John

[macboffin]

If aircraft are "no ailerons" you need a fair amount of dihedral for good control. Check out designs for early single channel models, you will see a significant amount of dihedral. A reverse Vee tailplane will give a slight positive roll input from rudder deflection,but unless the surfaces are large the effect is more theoretical than useful.A conventional tailplane+fins/rudders much preferable! Incidentally, with a fin on each boom-end only one fin has to have a rudder; that set-up works quite well. Regarding "radio-sonde" this was effectively a powered glider,whereas you have a higher power-weight ratio; in addition you are probably wanting a lot more manuvrability than a Radio-sonde configuration can give you. As to undercarriage, you could use a take-off dolly with large wheels to iron out rough ground, better than over-stressing the airframe due to acceleration etc from a catapault or high-start system; land it on a belly skid.

[Enoki]

Hello, red_gol
I appreciate your giant step.
I also worry about the recovery of a UAV. Do you think net is the best way?

If you try a net, please use it carefully. Somebody will mistake it mist net. Where do you live? There is a ban to protect wild birds in Japan.
Thanks, Enoki http://sky.geocities.jp/enokiec/

[skymind]

Very lovely red_gol. Did you add your own wing and tail or did you buy the entire aircraft from the Chinese company? Is it google-able?

[treehog]

in microlight aircraft and hang gliders especialy with slow speed sub 25mph flight aerlions often prove not to work

Instead they use dragerons basiclay airbrakes that pop up to drag the wing around

Some delta wings use twin rudders at the wing tips
They use the far inboard rudder to activate the turn and the other rudder on the outboard of the turn remains neutral

When landing both rudders deflected act as airbrakes


Aerlions are very effective control at high speed

Your planes has a high speed profile and looks best suited to
aerlions

However if you are going the slow flight route with dropped flaps then the use of augmented airbrakes dragerons or wing tip rudders might have a use

keep up the good work

I take it red_gol is based in mainland China

if possible will you be able to in the future make your own web site to keep us informed


Ralf

[skymind]

It crashed again didn't it red_gol?