By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by CML

Boeing B52 PSS Glider

BUFF is one of my winter projects

All Topics | Latest Posts

Search for:  in Thread Title in  
Erfolg02/12/2011 15:01:39
avatar
11881 forum posts
1376 photos
I guess you know that there is one in the Duxford IWM.
 
Many years ago my wife and myself stood underneath the aircraft in total awe of the size. The shear size of the UC legs alone were incredible. Although Jumbos seem big, it seemed bigger, it could have been a result of being indoors, certainly impressive.
 
I remember seeing a B52 flying low level along the Duddon Estuary, near Greenodd, as I was driving in the same direction along the side of the river. It was really low, just climbing to clear the hills, to fly on over Windermere. The next week or maybe a little later, I the same said thing happened this time with a Vulcan. On reflection, they were both surprisingly quite. That is after being surprised by low flying jets on various hillsides in Cumbria. Everything from a Phantom, and everyday Harriers, Hawks and Tucarnos doing the same run, week in week out.
 
I do remember seeing a model B52 at Rivington Pike at least 12 years ago, which was impressive.
Tim Mackey03/12/2011 00:16:07
avatar
20920 forum posts
304 photos
15 articles
Yup, the picture of the tail section is of that very one.
Now, back to the model - my mate Richie came over tonight with his fantastic home built 4 axis hot-wire CNC cutting rig! Its quite a beast as seen below.
 
General view.
Utilizing readily available materials, the all steel construction comprises two vertical towers which can be clamped to the work surface at whatever distance apart you require, and the two horizontal legs are at right angles across the surface. Threaded rods carry the cutting wire in both axis, but of course, with each post being independently driven by a stepper motor - this can move in 4 axis if required. The horizontal drive rail size allows for massive wing chords to be cut if required. The stepper motors are driven by a separate unit housed in an old desktop PC case seen here below the base board.
 
One end of the machine showing screw drives,motors and guide rails ( drawer runners ! )

The laptop and interface ....
Full 3D simulation of the programmed cut can be run before any foam is actually cut.


 
 
Heres the remains ( saddle ) after cutting one front fuselage section half
 


Theres a short clip of the cutter in action below.
I'll do one later of the whole process, so you can see the start up, and here all the whirring and clicking stuff....lovely
 

Edited By Tim Mackey on 03/12/2011 00:39:47

Tim Mackey03/12/2011 00:19:17
avatar
20920 forum posts
304 photos
15 articles
The whole cut is done in one action, bottom, inwards, upwards, outwards, up, in, and down etc. The clip shows it on the way back down and ready to finish off. We were a little disappointed with the finish - but that's down to the poor quality foam - nothing that a little sanding before veneering wont fix. All in all, a fascinating evenings work.
 
In the next few days, we shall do the tailplanes and fin, together with the tapered rear fuselage sections.
Phil Cooke03/12/2011 00:29:04
avatar
2727 forum posts
1915 photos
Awesome stuff Tim!! What a fantastic machine!
Tim Mackey03/12/2011 00:36:27
avatar
20920 forum posts
304 photos
15 articles
Isnt it ! The clever beggar made it all in a couple of days too !
 
Incidentally, if anyone has any cutting work that they need doing, Richie is happy to do so - but will of course charge a reasonable fee. All thats needed is a few basic details of the section, length of Leading and trailing edge etc...and away we go.
Terence Lynock03/12/2011 13:04:12
avatar
2453 forum posts
46 photos
Hi Tim,
do you want the plans for a B52 sloper? 78'' span, can send you the TIFF files if you want them.
 
Nah...Ill stick with this one thanks Terence.

Edited By Tim Mackey on 03/12/2011 16:42:21

Erfolg03/12/2011 13:31:08
avatar
11881 forum posts
1376 photos
I am impressed by the machine.
 
I am sure that it would cost a lot to build, without access to low cost stepper motors and interface, not withstanding the leadscrews etc.
 
All in all impressive machine (tool?) and the model build!
 
I am eager to hear more, I shall watch the thread attentively.
 
I do like the idea of the a wing cutting service, as "I could kill to birds with one stone", A day out with the better half and purchase some wings, happiness.
Tim Mackey03/12/2011 16:52:58
avatar
20920 forum posts
304 photos
15 articles
Didnt cost that much at all - job lot of stepper motors around £30 for 6
( only one of which was duff ) so four used and one is spare.
The driver interface was a tad more, but again....bargains from china to be had via ebay these days.
The lead-screws are simply threaded studding from a DIY shed, with a length of hex bar threaded to suit, that hold the cutting wire brackets
( simple brackets from the diy shop again )
The metal frame was welded up by himself, a bit of checker plate here and there.....
The clever software is simply Profili for wing sections ( pro version which allows for 4 axis ) and an another free downloadable package DEV FUS ( foam version ) for, errr, fuselages.
Finally, "Mach3" does the driving of the cutter itself.
 
The cutting is now on hold for a week or two due to holidays etc, but when we do the actual tailplane and fins, I will film the whole process - it really is most impressive to see and hear it all whirring away.


Edited By Tim Mackey on 17/12/2011 13:56:37

Tim Mackey03/12/2011 19:08:21
avatar
20920 forum posts
304 photos
15 articles
Indeed it is Tom - at the time, the largest RC model glider ever built, and in the Guinness BOR to boot. Simon plans to bring it to the Orme again for one of next years PSS meetings.
As for me...well, I simply wouldnt have the space for one thing.

 
And a rather youthful Phil Cooke assists Simon at an aerotow back in the 1940s

Tim Mackey03/12/2011 19:20:04
avatar
20920 forum posts
304 photos
15 articles
These days...its trailered.
Tim Mackey08/12/2011 14:04:17
avatar
20920 forum posts
304 photos
15 articles
Well it seems we had some erroneous data in our programme - the final shape ended up a bit off as it were - here on the left is the profile we ended up with, and on the right, is a quick mock up I did using my old fashioned bow and some ply templates taken off the plan.

TBH we weren't that happy with the finish on the foam anyway - recycled builders yard stuff which seemed to have a fair few hard bits in it - scattered randomly throughout, so this affected the cut - and the final finish would need a lot of sanding.
 
So.... I ve just had two more 8 x 4 panels delivered, and a quick test cut shows a much smoother finish. We just need to get the software data sorted now, and then its round two next week when Im back from Xmas visits down south.
 
My ABS engines arrived at weekend ( thanks Phil ) so Ill be doing them soon also. My plan is to trim and join as required, then fill with expanding builders foam to give some strength, before fitting to the pylons.


 
Tim Mackey17/12/2011 14:02:07
avatar
20920 forum posts
304 photos
15 articles
Ok, back on track with this project - the new 8 x 4 foam blocks were delivered, and a quick test shows them to be better than the first - no 'orrible hard bits in it. I've cut them up into manageable sized chunks, and then used the machine to square/true everything up. Its important that the block stands truly vertical with reference to the wire travel, so everything was trued up with levels, and the blocks then cut into the correct length for both the non tapered front sections, and rear tapered sections. I used a scrap offcut to do this little demo film of the cutter at work, and also to confirm that the newly drawn section was correct.
Tomorrow we plan on completing all the fuselage, and hopefully the tail feathers too.
Then I can get on in earnest with sheeting etc.
Phil Cooke17/12/2011 14:11:36
avatar
2727 forum posts
1915 photos
Great to see you making good progress on this again Tim, all the best for tomorrow's foamathon! Are you veneering inside and out?
Phil Cooke17/12/2011 14:11:44
avatar
2727 forum posts
1915 photos
BTW When I veneered some very similar sections last week on the A-10 fuz I noticed the veneer shrank a little, effectively opening up the U-section a little when it was still in two halves. I think I rushed the veneering and possibly the contact adhesive still had some drying and shrinking to do which caused it I think... Anyway one to watch.

Edited By Phil Cooke on 17/12/2011 14:15:43

Erfolg17/12/2011 14:22:43
avatar
11881 forum posts
1376 photos
Tim
 
The more i see, the more impressed i become.
 
It does seem that there is the bases for a number of articles on the
 
a) Construction of the machine
b) Software
c) Power supply, wire and set up, rates of cutting etc.
 
From my background and other ex-engineers I guess, it challenges very successfully preconceived, programmed reponces. No need for ground buttress threads with zero backlash nut assemblies, ground runners, rigid high mass frames etc.
 
It demonstrates the benefit coming to a problem asking, what is actually necessary. Above all ingenuity. All combined with a degree of the "Can do it" approach.
 
Model looks interesting to.
Tim Mackey17/12/2011 14:25:15
avatar
20920 forum posts
304 photos
15 articles
Posted by Phil Cooke on 17/12/2011 14:11:36:
Great to see you making good progress on this again Tim, all the best for tomorrow's foamathon! Are you veneering inside and out?
Nope, just 1.5mm balsa outside, then tissue/glass and PolyC.
Simon's plan does say that if you use a good ply spine ( which I am ) then inside veneer is not required.
Tim Mackey17/12/2011 14:28:00
avatar
20920 forum posts
304 photos
15 articles
Posted by Phil Cooke on 17/12/2011 14:11:44:
BTW When I veneered some very similar sections last week on the A-10 fuz I noticed the veneer shrank a little, effectively opening up the U-section a little when it was still in two halves. I think I rushed the veneering and possibly the contact adhesive still had some drying and shrinking to do which caused it I think... Anyway one to watch.

Edited By Phil Cooke on 17/12/2011 14:15:43

Thanks Phil - good tip...Ill be doing some test sections first.
I plan on soaking the balsa thoroughly, then wrapping it whilst still wet around each fus half section, securing with tape, and letting it dry thoroughly for a couple of days or so. Then, when removed I hope it retains its shape, at which point, Ill use copydex on both foam and wood. Fingers crossed.
Tim Mackey17/12/2011 14:30:40
avatar
20920 forum posts
304 photos
15 articles
Posted by Erfolg on 17/12/2011 14:22:43:
Tim
 
The more i see, the more impressed i become.
 
It does seem that there is the bases for a number of articles on the
 
a) Construction of the machine
b) Software
c) Power supply, wire and set up, rates of cutting etc.
 
From my background and other ex-engineers I guess, it challenges very successfully preconceived, programmed reponces. No need for ground buttress threads with zero backlash nut assemblies, ground runners, rigid high mass frames etc.
 
It demonstrates the benefit coming to a problem asking, what is actually necessary. Above all ingenuity. All combined with a degree of the "Can do it" approach.
 
Model looks interesting to.
 
Loads of self build "how tos" on t'internet Carl - and the prices of the equipment are reasonable too. I reckon the hardest part is learning the software. Ive been having a play around over the last few days, and as usual, actually practicing with the stuff is the answer - well it is for me anyway.
Erfolg17/12/2011 14:54:43
avatar
11881 forum posts
1376 photos
Tim
 
I suspect that you and your friend underestimate your achievement.
 
Many years ago, I headed a project to install a stepper motor system. The number of professional and technician engineers to build the system was considerable. The interface used Ladder Logic to set operational parameters so is immediately different. It did work as required, straight out of the box, but it took time and money. May be things are different now, more sources, broader knowledge.
 
I am impressed by all the achieevements, and being truthful, I am a ittle fearful in starting the project, without the crutch of a proven system. I will be trying, to fix a cost and source with particular emphasis on the control system (motors and interface). Part of the issue is identifying the current state of the art, rather the supplanted equipment or straying into cutting edge approach.
Tim Mackey17/12/2011 15:28:24
avatar
20920 forum posts
304 photos
15 articles
Oh I didnt do anything Carl....he built it all, and has pretty well got the programming sorted.
Ive just finished playing around with "devfusfoam" and think I have manged to create a whole new experimental shape - and figured out how to export the data as an ".NC" file which mach3 ( the stepper driving software ) requires
...so just off to the garage to give it a try.

All Topics | Latest Posts

Please login to post a reply.

Latest Forum Posts
Support Our Partners
CML
Subscribe now
Jetworks
electricwingman 2017
Slec
Sussex Model Centre
Sarik
Advertise With Us
Latest "For Sale" Ads
NEW POLL - has the pandemic altered your event safety perceptions?
Q: Has the covid pandemic deterred you from attending shows and events in 2021?

 No, I'll be attending just as many as I usually do
 No, but I'll choose my event with greater care
 Yes, I'll attend fewer events going forward
 Yes, I wont attend any where previously I have

Latest Reviews
Digital Back Issues

RCM&E Digital Back Issues

Contact us

Contact us

Magazine Locator

Want the latest issue of RCM&E? Use our magazine locator link to find your nearest stockist!

Find RCM&E!