HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jul 12, 2013, 03:27 PM
InceCreations
vincent123's Avatar
Joined Jul 2009
707 Posts
Build Log
FZx build: design phase

One of the next flying wing models in the FZ series, has to be with a ducted fan
A first attempt ...

Idea is to have a model capable of taking off from its belly and of course landing on it.

Fuselage will be cut from styrofoam, strengthened with spars/formers and planked with balsa, and eventually laminated with glass fiber epoxy.

Wings classic build up with balsa ribs and spars, as from my experience, this is still one of the strongest/stiffest and lightest way of building wings.

Span 1m (excluding fuselage of 100mm).
Angle of attack (on ground): 8°
Weight ca. 1,5kg

EDF not decided yet, should be a 70mm version.

Vincent
vincent123 is offline Find More Posts by vincent123
RCG Plus Member
Latest blog entry: FZ5: design phase
Reply With Quote
Sign up now
to remove ads between posts
Old Jul 13, 2013, 09:17 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,212 Posts
You could put a nose on it and use naca ducts for the intake?
http://static.rcgroups.net/forums/at...3-DSC01647.jpg
Pic from here

http://www.rcgroups.com/forums/showthread.php?t=1846718
I thought this would make a neat idea for a wing,with straight exhaust.
Stupot46 is offline Find More Posts by Stupot46
Last edited by Stupot46; Jul 13, 2013 at 09:23 AM.
Reply With Quote
Old Jul 13, 2013, 01:38 PM
InceCreations
vincent123's Avatar
Joined Jul 2009
707 Posts
Stuart, I must admit, you got always a good link up your sleeve !

The nose would be good to minimise drag when gliding, but wouldn't it reduce the dynamic air pressure at intake and as a result reduce performance ?

Vincent
vincent123 is offline Find More Posts by vincent123
RCG Plus Member
Latest blog entry: FZ5: design phase
Reply With Quote
Old Jul 13, 2013, 04:57 PM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,212 Posts
Quote:
Originally Posted by vincent123 View Post
Stuart, I must admit, you got always a good link up your sleeve !

The nose would be good to minimise drag when gliding, but wouldn't it reduce the dynamic air pressure at intake and as a result reduce performance ?

Vincent
Not my area I'm afraid,the guys on the edf forum will be able to give you the info.
From what I've picked up,if you size the ducts correctly and get a smooth passage to the fan it should work ok
Stupot46 is offline Find More Posts by Stupot46
Reply With Quote
Old Jul 13, 2013, 05:16 PM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,212 Posts
http://www.flyingmag.com/scoop-naca-scoop
Some info on naca ducts.
Stupot46 is offline Find More Posts by Stupot46
Reply With Quote
Old Jul 14, 2013, 06:19 AM
InceCreations
vincent123's Avatar
Joined Jul 2009
707 Posts
Wing to fuelage connection.

Not decided which material for the formers, I'm thinking of carbon plate, cut to size.
The formers will have to cope with torsional forces ..
vincent123 is offline Find More Posts by vincent123
RCG Plus Member
Latest blog entry: FZ5: design phase
Reply With Quote
Old Jul 14, 2013, 09:28 AM
less is more
Knoll53's Avatar
United States, CA, Marina
Joined Sep 2006
2,794 Posts
A one meter plane that weighs 1,5kg....That should be fun ! This one is really going to move ! My humble little floaty gliders would be no match.

The shape is great. Nice job with the 3D modeling. I like your big open free flowing intake duct. It should give the fan a fighting chance at producing some power. The belly has a ground contact point that appears to be in front of the CG. Depending on how slippery your landing field is, this could give you a nose high bounce upon first contact. Is this a concern?

Kent
Knoll53 is offline Find More Posts by Knoll53
RCG Plus Member
Latest blog entry: Nosey
Reply With Quote
Old Jul 14, 2013, 09:59 AM
InceCreations
vincent123's Avatar
Joined Jul 2009
707 Posts
Quote:
Originally Posted by Knoll53 View Post
A one meter plane that weighs 1,5kg....That should be fun ! This one is really going to move ! My humble little floaty gliders would be no match.

The shape is great. Nice job with the 3D modeling. I like your big open free flowing intake duct. It should give the fan a fighting chance at producing some power. The belly has a ground contact point that appears to be in front of the CG. Depending on how slippery your landing field is, this could give you a nose high bounce upon first contact. Is this a concern?

Kent
The contact point is indeed in front of the CG, not only important for landing, but I want to take off from the ground, so double!

The ground contact is about 85mm in front of the CG, the tilting will start when the motor pushes with about 1,8kg. I hope this point is not reached and the plane already start moving (when once in motion, friction drops).

Concerning the landing: "should" be not a problem: the relation CG versus ground point is the same as the FZ2, which lands easy.


Vincent
vincent123 is offline Find More Posts by vincent123
RCG Plus Member
Last edited by vincent123; Jul 14, 2013 at 10:07 AM.
Reply With Quote
Old Jul 14, 2013, 10:10 AM
less is more
Knoll53's Avatar
United States, CA, Marina
Joined Sep 2006
2,794 Posts
With that kind of power, I'd think that the take offs would be like a bungee launch. Just point and go. Of course, I'm a glider pilot so any power sounds like a lot.
Knoll53 is offline Find More Posts by Knoll53
RCG Plus Member
Latest blog entry: Nosey
Reply With Quote
Old Jul 14, 2013, 10:45 AM
InceCreations
vincent123's Avatar
Joined Jul 2009
707 Posts
I never bungeed, thereore I'd like to take off from ground.
Compared to the FZ3: it pushes max. 1800gr, and the maiden was not at full throttle when starting.
So it should work ... ?
vincent123 is offline Find More Posts by vincent123
RCG Plus Member
Latest blog entry: FZ5: design phase
Reply With Quote
Old Jul 14, 2013, 12:04 PM
less is more
Knoll53's Avatar
United States, CA, Marina
Joined Sep 2006
2,794 Posts
Yes, there is plenty of power.

That big smooth belly should be very good for your thick grassy landing strip. Even high speed landings should be smooth. I hope this project gets built. Maybe even touch and goes would be possible.
Knoll53 is offline Find More Posts by Knoll53
RCG Plus Member
Latest blog entry: Nosey
Reply With Quote
Old Jul 14, 2013, 01:47 PM
Registered User
iron eagle's Avatar
United States, MA, Middleboro
Joined Jul 2007
579 Posts
Quote:
Originally Posted by vincent123 View Post
Wing to fuelage connection.

Not decided which material for the formers, I'm thinking of carbon plate, cut to size.
The formers will have to cope with torsional forces ..
Vincent,
While some carbon fiber may be a good idea it may be overkill. As an example I will include a picture of the frame of a plane I built the uses the center section/fuselage to join and support the wings. The former are made of several layers of balsa with the grain running in different directions much like plywood. The formers combined with the fillets which blended the wing to the center of the aircraft have been able to carry the load very well.
iron eagle is offline Find More Posts by iron eagle
RCG Plus Member
Latest blog entry: The third time is a charm!
Reply With Quote
Old Jul 14, 2013, 04:15 PM
InceCreations
vincent123's Avatar
Joined Jul 2009
707 Posts
You are perhaps right, I tend to overdesign

I need to check how much the carbon plates weigh, thIs could be a knock out.
vincent123 is offline Find More Posts by vincent123
RCG Plus Member
Last edited by vincent123; Jul 15, 2013 at 02:33 AM.
Reply With Quote
Old Jul 14, 2013, 04:21 PM
InceCreations
vincent123's Avatar
Joined Jul 2009
707 Posts
EDF hatch should do the job.

I had to install it at the top of the fuselage, so I could fix the EDF carier to the first rib.
Will be a challenge to keep the top neat and clean.

Next will be the battery hatch.
vincent123 is offline Find More Posts by vincent123
RCG Plus Member
Latest blog entry: FZ5: design phase
Reply With Quote
Old Jul 14, 2013, 04:24 PM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,212 Posts
Check with the guys who know,but I don't think running a couple of tubes through the duct will hurt too much.
Stupot46 is offline Find More Posts by Stupot46
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Build Log ZDelta build: flies again! vincent123 Nurflügel 249 Jun 30, 2014 12:47 PM