Jump to content

Ben Buckle Falcon Build


Recommended Posts

Posted by Don Fry on 21/10/2019 12:12:06:

What motor/prop are you proposing to use.

I've picked up a 4250 500KV motor:

**LINK**

On 4s this should be good for 900w. I'll start off with a 15x7 prop and go from there.

I'm hoping to keep the build light, with all up weight less than 8lbs (hopefully less than 7lbs), so aiming for 100+ watts/lb

If I am struggling to get enough power on 4s, I will switch to 6s as the motor can handle upto 1350W.

As a backup plan, I am planning on positioning the firewall in such a position to allow a 5055 motor to be fitted if needs be. (i.e. if the build is overweight).

Link to comment
Share on other sites

Posted by Don Fry on 21/10/2019 12:54:30:

Cheers. As an aside, the 100 watt rule does not REALY apply to the one speed free flight types. 50 to 60 is plenty.

No doubt you are correct. I'm trying to 'guess' the minimum weight battery/motor combo I can fit to balance out the plane and produce enough power.

4-max recommend a 5055 motor for this plane, the 4250 motor I have selected produces the same power as the 4-max motor, but weighs a few grams less. (both are 500KV)

Link to comment
Share on other sites

Posted by Chris Freeman 3 on 21/10/2019 13:25:41:

Nice plane, they fly very well but the main wheels are very far forward which can make it hard to land as you have a lot of weight on the tail wheel, we built a double size one over 20 years ago and it kept on breaking the tail fin off in a ground loop.

Good to know. I'll make sure that area is strong!

Link to comment
Share on other sites

I'm not really an aficionado of vintage models for myself, but many of my club mates are. Several have fallen into the trap of over - powering R/C conversions of classic free flight models (IC and electric) and have inadvertently suffered catastrophic wing failure when now able to fly in conditions that would have grounded the FF originals. The extra power and R/C does give the old 'uns a new lease of life, but beware of the light construction for FF when flying them more enthusiastically than they were intended for. If sufficient extra strength hasn't been added to the original structure (wing spars in particular), think seriously of doing so. Maybe this has already been considered with the BB kits, but I thought I'd just mention it. as it's heartbreaking to see lovely trad models break up when pushed a tad too far.

Good luck and enjoy the build and flying yes

Link to comment
Share on other sites

Cuban is tight. Light winds, a chair without arms, a mind in a state of calm. When I smoked, if I wanted a fag, I put the transmitter down to roll and light one.

You can liven it up. A circuit at 2 meters. A 60 meter roll on the touch and go. Careful use of very little power. There was a build thread on this site where a greatly enlarged Junior 60 got built. It stayed aloft on 10 watts a pound if memory serves.

Link to comment
Share on other sites

Posted by Cuban8 on 21/10/2019 17:17:18:

I'm not really an aficionado of vintage models for myself, but many of my club mates are. Several have fallen into the trap of over - powering R/C conversions of classic free flight models (IC and electric) and have inadvertently suffered catastrophic wing failure when now able to fly in conditions that would have grounded the FF originals. The extra power and R/C does give the old 'uns a new lease of life, but beware of the light construction for FF when flying them more enthusiastically than they were intended for. If sufficient extra strength hasn't been added to the original structure (wing spars in particular), think seriously of doing so. Maybe this has already been considered with the BB kits, but I thought I'd just mention it. as it's heartbreaking to see lovely trad models break up when pushed a tad too far.

Good luck and enjoy the build and flying yes

Thanks for the tips, I'll bear them in mind.

I'm only planning on flying this slowly and leisurely - and with the motor off as much as possible. Looking at the plan (which I have been looking at for a couple of years), it does seem over engineered for a free flight model, and as such more suitable for RC than most free flight designs. This will be my lazy Sunday sitting in a chair on a nice sunny day flyer. Besides, the attraction was as much about the build as the flying! wink

If on completion, I have over powered it, then I could always run on 3s instead of 4s or change the prop to tame it down.

Link to comment
Share on other sites

I'm sure you'll be fine with the model if it's flown within reasonable power constraints and not forced to battle through windy or turbulent conditions or boredom sets in and you fancy some aerobatics (only kidding wink). Sounds like you have the right idea - nice and steady.

Build the wing as flat and as true as you can - with the dihedral of course - washout is not required IMHO.

 

Edited By Cuban8 on 22/10/2019 12:26:11

Link to comment
Share on other sites

No washout. These things give a minute's notice in writing it intends to stall, during which time you can let go of the elevator. They will sometimes stall, gently, if you abruptly turn to wind from slow speed, if you allow the nose to rise.

The only thoughts I have had about the structure is I reckon the fuselage formers aft of the wing TE could be replaced with depron, (optional,with some thin balsa stick glued on the faces), the wing ribs away from centre section ditto, the equivalents of wing ribs in the tail fin and tailplane, ditto.

Save a lot of weight, and nearly all aft of the CG.

Closed loop, Dacron, working the tail feathers, with the adjusters at the servo ends. Again get weight away from the back end.

I did some calculations once and I think it would remove about  200 to 300 grams of lead from the front. Because the solid iron lumps on the originals were heavy, that is a good thing. And 300 grams of  structural weight. That's 500 g plus,  for no loss of structural integrity.

.

Edited By Don Fry on 22/10/2019 13:15:22

Link to comment
Share on other sites

The Depron tip is a good one. I only 'discovered' Depron after it was called for in my Revolver II build, never used it before and am very impressed with the stuff. Will certainly find appropriate use for it in other builds where weight needs to be saved - particularly at the back end. Don's also right about the extra strength given to Depron formers by adding thin balsa or perhaps 1/64 ply for larger parts. Made up some test pieces as a 'composite sandwich' and the results were very encouraging.

Edited By Cuban8 on 22/10/2019 15:32:55

Link to comment
Share on other sites

  • 5 months later...
  • 1 month later...
Posted by David perry 1 on 06/04/2020 20:04:56:

How is this amazing model progressing?

Slowly! It took me a while to recover from a spinal injury last year (which is why my wife purchased this kit for me), and this year I have not had a single day off work (not even bank holidays) due to the coronavirus pandemic. surprise

Progress so far: Tailplane & fin - awaiting sanding & shaping, one wing panel - awaiting sanding and shaping. Just started on second wing panel.

I have however decided on the all important colour scheme......

20200119_153532.jpg

20200119_203609.jpg

20200530_171100.jpg

20200602_104019.jpg

20200602_104042.jpg

Link to comment
Share on other sites

Posted by Denis Watkins on 02/06/2020 20:27:14:

Cover that magnificent structure with " see-through " covering

Indeed! I want to be able to see the intricate structure when its done. The scheme will be transparent gold and white.

Thanks!

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...