RE: BVM T-33 AFS Build thread
 

Mark,

I am very concerned by what you say, the personal scathing attacks were certainly relentless a while ago, but now to my limited view seem much better ordered.

I had not seen you a victim here, but then frequent only a limited part of the entire forum. That someone with your kindness of support, genuine interest and guidance loses the will to participate because of a few bigots and XXssholes, is truly despicable, but I support your intention.

I would like to keep you in this loop if you are OK, so may I send you a personal update and pictures, as well as continuing to run the thread?

I have really valued your contribution, expertise and support and would hope I can with your permission retain such a relationship.

With genuine regards,


Garry

RE: BVM T-33 AFS Build thread
 

Garry...
Please by all means, contact me directly at any time.
It has been my pleasure working with you, and I look forward to it in the future.
Again, if I can be of any assistance, please call on me at anytime.
I look forward to meeting you someday, and talking jets over a pint.

Best Regards

RE: BVM T-33 AFS Build thread
 

Mark,

Your on, the beer will be on me for the evening!!!! Could you PM me with your email address, have had some gremlins on Outlook (have not we all!!!).

Can't recall whereabouts you hail, but She Who Must Be Obeyed is suggesting a Florida Holiday in 2006!!!! Let me know if you hit these shores, I can make most parts of the country in a few hours.

By the way, I will post some pictures on the flaps, I made significant progress on one of them last night, having cut the wing down, added the ply cover, installed the wood carbon support brace, and started to make up the servo holders.

I think that some of the wood in the flaps pack is cut so that it must reinforce the area behind the phenolic tube, but I was too tired to get the plans back out. Else there is a big hole to look up.

It is good stuff and I was dreading this, but feel that it is going the right way. Watch me cock up now!

All the best,

Gazzer

RE: BVM T-33 AFS Build thread
 

OK,

so the flaps......... right, well Mike Cherry once reviewed the flaps for a P80 when the kits were fairly new and he remarked how complex they were. The AFS kit has been simplified, but I have to say that I have struggled, but I doubt it is the fault of the kit!!

Cutting a long story short.........

If you've never seen one, the theory is great. Rather than have a whole trailing edge cut from the wing and acting as a flap, you have a flap skin, no trailing edge, a wooden support structure across the top of the flap skin, a torque tube glued to the front that has a pin mount on one end, and goes through a plastic bush on the other, that fits through a wooden structure to which the servo is attached.

The servo links to a torque arm that has a sqaure brass tube glued into it, this mates to a bigger brass square tube that is glued in the torque tube (a carbon tube). You simply slide the brass tube on to the brass tube, push the wing on, and it lines up to a plastic tube glued into some wood structure just before the aileron starts.

Looks great and works well.

I did struggle, partly through not following the instructions to the letter. I had the main issue in that the torque tube had quite an angle to go through from where it exits the wood structure in the fuz, to where it is pinned in the wing. I had to remove far more of the back end of what would be the trailing edge, to allow the carbon rod to be straight. I thought perhaps the wood structure was too far back but checking it does fit where it should, and it joins up formers in the belly. Perhaps had one manufacturing tolerance to the other, but more likely it was me being just a few mm out, it has happened before.

Anyway, after some deliberation, I removed a bit more of the wing, and the tube runs straight. Had a nightmare joining the flap, again did not follow the instructions, and thought I had tack glued the rod with some CA to get it right. The glue had run 1/3rd the length of the rod, and was bonded permanently, and of course was misaligned.... aaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhhhhhhh!!!![:@]

But of course thats what they make debonder for, so this time following the instructions, all was sorted.

I then noticed that the flap skin was not straight and in fact undulated like a roller coaster.......... You will see from the hopefully uploaded pics, that I have used a couple of steel rules above and below the trailing edge balsa block that is stuck to the flap skin, that should straighten the skin out, especially with the basswood lattic work that is also attached.

The pics show the whole thing being glued up with slow CA.

Just before this step I had the flap moving up and down.... exciting. I have not used powerful digital servos, but am worried cos this one hums a lot. I can play with the flap and relieve the hum, but everytime I reselect a flap position, it starts again.

Should I be worried? I will be oiling the plastic bush and may even just shave a tiny weeny bit of the shaft where it goes through the plastic bushing as the fit is a little comfortable. I am also going to reglue the smaller brass tube as there looks to be a tiny amount of slop.

I will also be making up a new torque link. I had not reversed the servo prior to setting up and it shot to the down rather than up position and would not traverse any more. Bent the link without even thinking about it!!! Strong stuff these servos.

So, this must have taken me about 5 hours so far, I feel reasonably confident about the next flap and will follow the instructions to the letter. The only thing that does still worry me is that the flap is just under the surface of the fuz when in the closed position. I will wait to see if the other one comes out the same, but may need to make up a bit of filler and bond this to the skin to the contour of the fuz, but we will wait on that one!!!

Gazzer

RE: BVM T-33 AFS Build thread
 

Gazzer,

With digital servos, there is buzzing, and there is buzzing. You have to make sure that the buzzing is not a result of the servo really being bound up by problems in the linkage, that can cause excess current drain in the best case, and overheating and failure of the servo in the worst case. However, sometimes a digital servo will buzz even if there is only a small amount of pressure on it. For example, I have built several BVM Kingcats with digital servos on the flaps. When the flap comes up, there is a hard stop, and if the flap servo is trying to drive the flap past that hard stop, bad buzzing occurs because the servo is drawing a lot of current trying to move the surface past the stop. Here you have to limit the servo travel (with a Matchbox), or adjust the linkage so it doesn't happen or the servo will burnout. However, on some of the Kingcats, one or both of the servos would buzz with the flap in the middle position - just because of the weight of the flap on it - the linkage and hinging at that point was completely free. In most cases (but not all) I could stop the buzzing by gently lifting the weight of the flap off of the servo. In this case, buzzing is not bad and the servo will be OK.

Most of the time, you can tell the difference by the loudness of the buzzing. A better way is to put an ammeter in the line to that servo and see if its drawing excess current. If the servo is buzzing, but you're drawing the same, or only slightly more current than at idle with the linkage disconnected from the servo, you're OK. If its drawing more than that, you have some work to do...

Bob

RE: BVM T-33 AFS Build thread
 

Bob,

great advice, I will check with an ammeter. The buzz is like you describe with the King cat weight of the flap. If I take hold of the flap and place just a little gentle pressure up or down, the buzz will stop, but as soon as i move the surface via the transmitter, then the buzz starts again. I will oil the bushing and double double check, but will heed the advice!

I have checked properly and there is no binding or stall in the distance the servo can travel, and the alignment is fine. I guess the principle of leverage means that the flap places a reasonable amount of pressure on the servo. Also as the airframe is really empty right now, I guess the sound is a little amplified!!

But I am taking no risks, so an ammeter is a good discipline and alll I have to do now is work out how to plug one into the circuit!!
:)
Thanks,

Gazzer

RE: BVM T-33 AFS Build thread
 

Gazzer

Good to hear from you again after the long silence! Aren't BVM kits fun to build? I now know why you were absent for so long. You have been working on your flaps!

I thought it was something serious like your wife finding your credit card receipts!!

John

RE: BVM T-33 AFS Build thread
 

Hi John,

Absence makes the heart go quicker!!!!

I was amazed to note that my last pictures were taken on the 12th of January!!!

Incidentally I holidayed in Orlando and visited the factory in April last year, the kit arrived some 6 weeks post the holiday, so it is nearly a year old and excluding the finishing/paint job I estimate the job to be 1/3 completed!!!

Strangely during a family discussion, the budget on the jet was pointed out to me by She Who Must Be Obeyed, and that I had clearly exceeded this by 25%, so at least I am getting away with something as the budget is probably 50% over and still climbing!!!

I must say that whilst I face a continuing stream of challenges, I am enjoying the build and becoming, at least to myself more accomplished and capable!!

Ideally immediately finishing this one, I would like to build another one!! But someone might take a lot of persuading, along with the bank manager!!

It is true to say that money is not the most precious thing to us, but time is about the most and usually the rarest desirable commodity, and it is one thing that challenges me nearly all the time!!

Gazzer

RE: BVM T-33 AFS Build thread
 

Gaz - Bob's suggestion about using an ammeter definitely helps ; if you don't have one immediately to hand, here's a trick I've used a few times: just turn the aircraft around such that gravity does not work against the servo. e.g. for the case of flaps, rotate the aircraft onto it's side (aka on knife-edge), then exercise the control to see if the buzzing stops or at least diminishes noticeably ; if it does, then the buzz is simply the servo working to hold the control surface against the pull of gravity.

Gordon

RE: BVM T-33 AFS Build thread
 

Should a digital servo buzz under no load?

RE: BVM T-33 AFS Build thread
 

I've noticed a few servos buzzing very quitely on the bench with nothing connected to it, but nothing like what you hear on the KingCat flap servos for example. In that case though, the surface its attached to probably amplifies the noise.

The best way to tell if everything is OK is by measuring the current into the servo. Somebody makes a gadget that does that, but I can't remember who. Anybody?

Bob

RE: BVM T-33 AFS Build thread
 

http://www.horizonhobby.com/Shop/ByC...?ProdID=HAN172

RE: BVM T-33 AFS Build thread
 

That's it, Gordon, thanks! Much easier than trying to hook your generic ammeter into the servo/RX connection.

Bob

RE: BVM T-33 AFS Build thread
 

Brief update.

Guys,

Since the last post I have not done any more work on the T-33. We are about to move house, and this coupled with some crap at work means no time. The good news however is several fold,

Firstly, the new house has a garage which is to be converted into a workshop. No more building in the attic which runs from - 5 to 100 deg most of the time, is too small and dark.

I am acquiring a compressor so have a way of doing the painting when finally finished!

I have bitten the second bullet and now ordered a replacement flap kit, so that the problem with the flap being under the surface of the skin, can be rectified.

So expect some progress around September. In truth, there is not that much more to do, when the flaps are finished, and it should go together a lot quicker than the progress I have so far made. Ian at Permagrit built one of these in 10 days, but he does know what he is doing!!!

I wrote this partly because a T-33 made it to the WJM this year and got my juices going, it still is a pretty airframe, and partly because I have had a few PM's from people asking how it was going!!!!

So, another year older and hardly done any flying or modelling this year at all in reality, but as we will be broke moving to the new place, I will have plenty of time on my hands!!!!

Maybe looking to finalise for Christmas 200...........

Gazzer

RE: BVM T-33 AFS Build thread
 

Just to report, have moved, workshop full of everything, no room to swing cat let alone build........[&o]

Work over rated, fun underdone.[:-]

Withdrawal symptoms!!

Flap kit arrive from BVM, 4 weeks and should be up and running again!!;)

Good job I don't write reviews for a magazine, eh?!!!!!!!:D

Gazzer

RE: BVM T-33 AFS Build thread
 

hi ya Gazzer,

I recon your next Rookie flight is long Over due.. you best get yourself down to L.M one of these Mondays.If you do then your workshop will soon be cleared out and you will be building your toy plane ready for the new season.. only 6 months to go.... yawn.

rgds
jason

RE: BVM T-33 AFS Build thread
 

Hi Jason,

You know, that sounds a damn fine idea, are you up there Monday 24th? Half term is on so might be allowed a sneaky excursion?

How are things with you, I think a package was on its way at some point wasn't it?!!

Gazzer

RE: BVM T-33 AFS Build thread
 

Yes we are there on the 24th! get down there for sure if you can. I am taking the boomerang just to give it another test flight or two before we go off on our jollys to florida.

yes the package was delivered on the 31st of august at 1.00am. A little jet pilot called Ethan James.

see you on the 24th

jason
p.s let me know if you are going an i will bring a extra tranny

RE: BVM T-33 AFS Build thread
 

Hi Jason,

Congratulations!!!! Fatherhood is great and little boys potentially will follow the footsteps!!!

I will be going on Monday subject only to the weather, and if its OK a good friend ofmine who has helped me a lot would like to come too.

I'll PM and mail you, but really appreciate the offer,

Gazzer

RE: BVM T-33 AFS Build thread
 

Hi Regarding the digital flap servo- they all buzz that is "normal" for a digital. BUT you really dont need digitals on the flaps and JR lately does not recommend using digitals on hard stop applications as if they jam up against a stop the current draw is enormous and can cause a drained battery quickly. On the T-33 the flaps are not that large, the airspeed is not that high and a good analog is perfect. Scott

RE: BVM T-33 AFS Build thread
 

I am agree with GSR, I have instaled analog servos -futaba 9402- in my BobCat flaps and it works flawless.

BR

Jesus

RE: BVM T-33 AFS Build thread
 

Hi Guys,

I went with BVM's reccomendation!! Now I have bought the Digital servos I will keep them, but I think next time, I will think about working out the torque rates and stuff. You only use these servos for about 10% of the flight, important parts yes, but so long as what you put in is powerful enough, the flaps are not that critical for response and accuracy I would guess. I mean I will be using the servo slow option on the PCM10!

Gazzer

RE: BVM T-33 AFS Build thread
 

Gazzer who???

Well here is a story about running before you can walk and how to waste a "lot" of money.

But,now at the tender age of a mere spring chicken of 46, it is nigh on 6 years ago since I treated myself to a jet and turbine, the BVM T33 here and a Wren 54 MKIII.

I then proceeded to start the kit, build and run the engine, but time was against me, especially stick time for flying. 2 or so years ago, I had that summer where everything I had was buried into the ground, creating immense disillusion......

Money and time was against me, I had a teenage son playing rugby for County and we seemed to spend all our free time at some rugby club or another. The wife and I discussed the merits of giving up. Money was a bit tight so I made the worse decision ever and sold off most of my modelling items, including the Wren...... but I could not get rid the T33 or the intention to still finish and fly her in a tiny part of the rear of my mind.

The son is now at university, and my wife works very other Saturday. We have moved house since I started the kit, and I now have an adequately sized garage to work in.

I found myself on Saturday digging out the manual and the boxes and stuff on the top shelf in the garage.......... then mircaulously somehow a DSX 9 JR transmitter got bought with my secret credit card!

So, Gazzer...... is tentatively back......... Hello again!!!

OK, lessons learned, time is not a barrier, and take it with the building, but make goals and progress.

Start buying the items slowly but surely and used quality goods are fine.

Gotto get me a turbine though, and yes, I would like a Wren, preferably a Mk III again to get me back to where I was.

And to get me started, I am allowed to buy a helicopter, just as our garden is big enough to practice in.

So this aged thread is going to get a fresh burst of controlled and measured enthusiasm, and I intend to finish the airframe well in time for my 50th, and ensure its maidened for my 50th.

As I start up again, I realise that my good friend Dave Burgin "Treadstone" who passed away a while hence, is not here to take the mick, encourage and berate me.

So, when ready, the model will feature"Treadston" proudly emblazoned as the co pilots nick name in the back seat, knowing he is there to help and guide me and look after me, it should make us all realise just how lucky we are when our life minutes are still being used.

I will start collecting the needed items, servos, engines etc from now, so if you have any T33 related item that you think might be of value (any broken parts that I can practice on!!!) let me know as I did not sell the items well, those whou bough from me got a really good deal!!!

I also have a better digital camera, so pictures will be included.

Hope to make the great buddies and acquaintances as I did last time but this time, there is a good reason to finish, let's get Treadstone in the air! :)

Regards,

Gaz

RE: BVM T-33 AFS Build thread
 

Hi Gary , glad you are coming back into the hobby have fun.
Time passes so quickly must have been Mmmm many years
since you went to jetpower.

Rgds Martin.

RE: BVM T-33 AFS Build thread
 

Hi Martin,

Yep that was one cool adventure and the fun and people we met, what a great weekend!!!

Got to simply get back in but steadily and sensibly!!!

The need for that whistling howl of power in the back garden of a turbine spooling up is just so needed!!!

Catch up soon!

Gaz