Here is a list of all the postings Trevor has made in our forums. Click on a thread name to jump to the thread.
|Thread: Panther Trainer Autogyro|
A question for all you seasoned Panther owners: What are you doing with the blades for transport/storage?
I had initially intended to leave them attached, hoping to devise some sort of blade caddy to support the blades above the rear of the fuselage, However, unlike helicopter blades, the Panther's don't readily fold back over the top of each other so this looks to be tricky.
Second thought was to unbolt the blades from the head plate, but this sounds like a recipe for getting through rather a lot of nyloc nuts
Third thought was to detach the headplate and blades as one unit. This looks to be favourite, but there's still the problem of the blades fouling each other when you try to fold them back. see pic:
Any suggestions, anybody?
Brilliant! Congratulations! Any tips to pass on to those of us about to embark on Panther maiden flights?
Edited By Trevor on 07/06/2013 16:52:56
Got a late e-mail yesterday declaring that this evening's club night would be a 'bring a model' night so I've been slaving over a hot iron trying to get the Panther at least to look finished. Actually, there's really only the battery/receiver/ESC stowage to be sorted out so it's nearly there.
Weight with a 3s x 3000mah LiPo is 3lb 12oz and it does look as if it might need a bit of noseweight so it will be close to 4lb when ready to go. The blades seem to spin up okay and run smoothly and everything moves the right way. What have I forgotten?
Blades are striped on the top but plain blue on the bottom, hopefully to aid orientation. Spats and subfins are yellow on the outside and blue on the inside for the same reason.
I really must cut that grass - there are wheels there, honest!
Decals are from Tim at ModelMarkings.com, except for a few more orientation-inspired yellow circles on the underside.
Do you get the impression that I am worried about orientation?
What with Stuart and Steve's Panthers and Dave's biggie finished, it sounds like there should be a rash of maiden flight videos soon. My Panther too is now more or less covered so should be ready to go sometime next week - and John has a new colour scheme to try out too. Watch this space!
Steve, being the coward that I am, I'm circumventing that challenge by going for the open cockpit and windshield option!
If you have balanced the blades then, as long as they are spread at 120deg to each other their combined cg is at the spindle, so it doesn't matter where they are pointing.
Well, I have now proved this for myself. I got bored with the last throes of blade balancing, bolted them to the head plate, took the gearbox in my hand and ventured out into the garden. Slowly but surely, the blades spun up! I didn't let them get up a lot of speed because I was having trouble holding onto the gearbox as the wind gusted around the trees. I still find it puzzling how the blades 'know' which way to go, just on the profile alone, with no rigging angle at all, but it works.
A few pics from today:
Rotors fitted - just the spats to go, then I really will have to work out a colour scheme.
The wing nuts are temporary - honest!
I've watched that video of Rich flying Bill's blades a few times now, and most instructive it is too. However, I am intrigued that the blades seem to spin up so well, without the benefit of any headwind, in spite of no shims being fitted.
Rich, are you able to predict from looking at a blade's section whether shims will be needed? The wood I chose for the leading edges is a fairly mean 6mm thick rather than the full 1/4in reflected in the plan drawing. Added to that, I haven't taken the trailing edges down below a millimetre or so, so the overall camber of my blades will be a bit less than the drawing. I was planning to cover the blades without any shims added and then fit 0.4mm ply shims with double sided tape so that they can be removed or added to easily. FWIW, I expect the AUW to come in at about 4lb.
BTW, for anyone coming late to this thread, my progress to date is now summarised on my website at:
Good stuff! It's great to see all these photos from you people who are running just ahead of me
Here's where I'm at:
With just the blades, spats and covering to go, it weighs in at 3lb 3oz with a 3000mah 3s LiPo. Does that sound about right?
John, Sorry to hear about the mishap. If you are thinking about alternative mast construction, my first thought would be 3/8in balsa core (with some lightening holes if you are that way inclined), with 1/32in ply skins on either side. You would though still have to work out an arrangement for the tongues. That said, Rich's cross grain laminated balsa setup seems pretty solid to me - but then my Panther hasn't left the bench yet, let alone the ground!
I agree about the disorientation - I lost my Rotorshape to that a few weeks back, and it also accounted for my Logo 10 helicopter a few years ago. With the Panther, I plan to do the inside faces of the wheel spats a different colour from the outside faces, since, with the Rotorshape, I often found myself looking at the wheels for a clue as to which way it was banking or turning.
I have no autogyro experience yet but have always found the collet type prop drivers to be perfectly secure - once I realised that you do have to do them up suitably tightly to ensure that they are properly clamped onto the shaft.
I did though encounter one model shop proprietor who insisted that there was no such thing as a 3mm prop driver and that a 1/8in one was what I needed. I wonder whether this might be another reason for people's distrust of collet-type adapters?
I suspect that it's a bit like battery connectors - we all have our preferences but the truth is they all have their pitfalls but can be perfectly reliable if used with suitable care and attention.
Rich, out of interest, for us all-electric folk, what rpm do you get out of your os40 four stroke on, say a 12 x 6 prop? I've converted a number of i.c. designs to electric over the years but still haven't got a real feel for power equivalence, mainly because the electric conversions have tended to come out anything up to 30% lighter.
Thanks for the pics Steve, very nice. I reckon I'm about one week behind you so it's very handy to see these progress shots.
Any pictures Steve?
Barry, the problem with applying large areas of film over film is trapped air bubbles so, if your stripes are more than an inch or so wide, I would vote for leaving gaps in the first colour, aiming for overlaps of 3-6mm. Alternatively, you could do a complete base covering and then apply the stripes from self adhesive trim or vinyl. This can be floated on over a film of soapy water, then the air and water can then be squeegeed out. Messy, but effective. The only snag is that the trim doesn't stick as well as iron on film so do make sure that any exposed edges face downstream and maybe seal them with a bit of fuel proofer. A cool iron can also be used but practice first - the temperature range between enhancing the adhesion and melting the vinyl is quite narrow!
So, two votes for a bench sander, then. Great videos BTW. I am though rather short of bench space so am still interested in any alternative tooling ideas (preferably hand held) for shaping the blades.
Thanks to all who posted about wood for the blades. I spent a good 20min yesterday on the floor of the B&Q warehouse using their wood to improvise a balance beam trying to select some 6 x 18mm pine strips of similar weight - should have taken the scales with me instead of the measure!
So, having now got the wood, next question: If there is one tool I should buy to simplify the job of shaping the blades, what would it be? A clubmate has offered me the loan of a section template or jig so my question is really about sanders, planes or whatever.
Thanks guys. If pine is okay, I'll get back to B&Q. I was fixated on the idea of ramin when I dropped in last time.
Can someone remind me of likely sources for the hardwood for the blades please. My local B&Q hasn't got any ramin and the assistant assured me that they don't do hardwoods at all any more (not sure I believe that).
I have no real feel for the relative merits of pine, ramin, basswood, obeche etc. for the job. Are folk managing to buy prepared strips or are you stripping them out of sheet wood?
Very smart! Is anybody keeping count of this growing pride of Panthers? I know of at least three more underway down here (Hants/Dorset border) that haven't yet graced this thread.
Thanks RIch. I will post progress pics but it will be a while before the Planeta gearbox bearing is put to the test - this is all I have so far:
I have learned such a lot from this thread and so far have little to contribute in return. However, on the subject of motors and cowls, I was hoping to avoid the need for a detachable cowl by moving the motor bulkhead forward and mounting the motor from the rear, like this:
This photo is of a larger motor from another project - the cross mount on my Panther motor has a larger overhang so the captive nuts wouldn't be so close to the edge of the cutout . Should work, shouldn't it??
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