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HelicopterTurbine Helicopters › PHT2 in a 212
06-04-2009 07:16 PM  8 years agoPost 1
Peter WalesrrElite Veteran - Orlando Fl - My Posts: All  Forum  Topic

For several reasons I have to leave my bigger heli projects and I decided to get on with something with the PHT2 I bought. I decided on a 212 as I have a calendar with a beautifully painted one and am going to try and copy that color scheme. All will be revealed later.

So I ordered a 212 for the Extreme from Joe and when it arrived I got stuck in. This is what I found when I opened the box

Very pretty and very small in comparison to my other models. I should be able to handle this one by my self which will no doubt be a relief to Darrell. It's not going to be a super scaler, I want a model I can fly a lot without worrying about damaging it and I don't want to spend months building it. I have 2 other ongoing projects for that.

The first job was to set up the turbine. I added lots of parts from my junk box. Started with an Extreme rotor head and ancilliaries and then I found some 8711 servos and metal servo arms. A quick search of my push rod box found suitable length rods and new ends got the servos installed.

Then I had to set up the headspeed. It is adjustable, but only within limits and I am stuck with 1500-1700 rpm. I opted for 1500 to start with, which leaves the turbine at the bottom of its power band, but I don't want it turning the head too fast. Its a long time since I set a headspeed greater than 1000 rpm. I'll be using 700mm blades plus or minus a bit.

Peter Wales
http://scalehelicopters.org

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06-04-2009 07:52 PM  8 years agoPost 2
MattJen

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UK

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Nice,

is it me, or is your fly bar bent ? it seems to droop..

Matt

All The Best

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06-04-2009 08:09 PM  8 years agoPost 3
Peter Wales

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Orlando Fl

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I thought that when I first looked at the photo, so I checked it and its straight. Then I noticed my doors were bent as well! It must be something to do with my little camera lens but I hate to get the big camera out and take snaps with that when I can simply take out my credit card size casio and take a snap.

I'll step back a little and see if it takes a better one

Peter Wales
http://scalehelicopters.org

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06-04-2009 08:15 PM  8 years agoPost 4
MattJen

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UK

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ha, it must have an anomorphic lense

Nice to see another project, and it is one that i would feel comfortable with flying as it is not too big..

I am subscribed to this build..

Thanks

Matt

All The Best

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06-04-2009 08:17 PM  8 years agoPost 5
Peter Wales

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Orlando Fl

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More like a crapomorphic lens for close ups.

That better? I took it further back and did some cropping

Peter Wales
http://scalehelicopters.org

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06-04-2009 10:18 PM  8 years agoPost 6
Notar

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Taxachussetts

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You cannot appreciate the size of the turbine unit by the pics. Its a gem.
Joe

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06-04-2009 11:09 PM  8 years agoPost 7
seattle_helo

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Seattle, WA USA

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I've said this before but I really can't get over how small that PHT2 is. Looking at the servos certainly puts it into perspective. Very cool.

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06-08-2009 07:22 PM  8 years agoPost 8
Peter WalesrrElite Veteran - Orlando Fl - My Posts: All  Forum  Topic

This thing is starting to look better and better. I spent the weekend building up the wooden base which supports the extreme mechanics and tried the turbine in their place

The tail drive lines up perfectly and will make a nice straight run. The only problem is going to be in the exhaust but I am sure Tam will be able to fix that.

I am going to have a break for a few days while I travel up to Nashville for their scale contest this weekend. I hope to see some of you there.

Peter Wales
http://scalehelicopters.org

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06-16-2009 11:51 PM  8 years agoPost 9
Peter WalesrrElite Veteran - Orlando Fl - My Posts: All  Forum  Topic

Back to work. The hole in the front was enlarged so the nose fitted easily, then the chassis was trimmed so the nose would pass it when I finally assembled it. I wanted to leave it open until the last minute as it will make it very easy for access and also I will be able to assemble the floor etc in the nose before fitting it.

The chassis is fitted firmly to the fiberglass with PFM and will get another filler coat tomorrow. The main suspension points are the two small box sections where the mechanics are bolted to and I wont be using them so I will make sure everything is well glued in. Then I will fit the two extra pieces of ply on the top and add the right angle brackets with blind nuts in them, to hold the mechanics in place

The tail rotor gearbox was assembled and so was the 40 degree gearbox. Once I have the glue in tomorrow I can start aligning everything up and fitting out the tail boom.

Peter Wales
http://scalehelicopters.org

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06-22-2009 07:34 PM  8 years agoPost 10
Peter WalesrrElite Veteran - Orlando Fl - My Posts: All  Forum  Topic

Work has been proceeding despite the silence. Its mostly the boring assembly stuff which is common to most helicopters so I haven't gone into great detail over it.

The first thing I dd was to find some way of getting the tail drive out of the turbine. Jetcat have supplied a driveshaft which is only 5mm diameter and none of varios stock items are this size. Fortunately the bottomless junk box revealed a coupling I had made earlier which had a steel sleeve fitted into the plastic coupler and it was bored out to exactly 5mm.

The next job was fitting the tail rotor gearbox to the fin, drill a big hole and apply lots of Hysol.

I dug deep into the junk box and found this plastic bellcrank. Vario supplied a wire pushrod which fits into a plastic tube which fits into an aluminum tube. I preferred carbon push rods and once I had worked out the geometry cut some to fit. The bellcrank was mounted on a couple of ply offcuts and glued into place with 5minute Hysol

Then the intermediate gearbox is fixed to its wooden mounting plate, lined up and glued in place with more Hysol

The bungee cords are holding the tailboom in place while the Hysol sets.

Now I have the driveshaft and the pushrod in the main tub and can work out the mounting of the mechanics and the tail servo.

Peter Wales
http://scalehelicopters.org

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06-27-2009 10:16 PM  8 years agoPost 11
chinnook

rrApprentice

Corpus Christi TX USA

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Hi Peter, did you cut the driveshaft yet to the mechanics? I am in the same stage of buildup. Just wondering if I should permanetly mount the boom like you then cut the shaft. Thanks Rene

chinnook

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07-05-2009 11:41 PM  8 years agoPost 12
Tromilu

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Copenhagen - Denmark

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Making almost the same project
Hello Peter Wales.

Very interessting to see your project. I am building the same project, PHT2 in a Vario Bell 212/412.

I have choosen to build the fuselage in the Bell 412 version. So far I have rejected all the woodwork and build a complete new set of frames and formers. The reason why I rejected the woodwork is that I want the fueltank to sit exactly under the mechanics. I managed to fit at 2 liter fueltank underneath the mechanics and together with a ½ liter hoper tank the fligth time will be enough for me... 11-14 minutes.
Next challenge was the exhaust system. I met Zimmermann at a Hobby show in Sinnsheim in Germany, he makes the nicest stainless steel muflers and pipes. He accepted my challenge to build me an exhaust system. I designed the system and made drawings of the exhaust in AutoCad and send him the files and shortly after I received at super cool exhaust, fitting just perfect.

In the front (under the cockpit)I plan to install a ECU, receiver and a Virtual Flybat System. Out in the nose section I have made space for the turbine starting LiPo battery and 2 x 2S LiPo packs for the receiver. Electrical power is supplied by a PowerPack Gemini system.

Still have a major problem to find a way way out of: main rotor shaft.
I want my model to be a Bell 412, having a fourbladed rotorhead. But the main rotorshaft that the PHT2 mechanic is shipped with is designed to fit fx 2 bladed flybarheads from fx Vario. I need to have a fourbladed head install, but the Vario head does not fit. The pin bolt through the main shaft, securing the head to the shaft is sitting way to close to the end of the shaft to accept a Vario fourblade head (bolt thru must be sitting 35 mm from the end of the shaft. Mayby some of You folks have an idear how to fix this problem.

I hope to see some of your projects.

Regards,
Troels Lund (Alias Tromilu)
Roskilde - Danmark

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07-06-2009 02:24 AM  8 years agoPost 13
Peter Wales

rrElite Veteran

Orlando Fl

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The exhaust looks great. I am having Tam make mine in California. I hope it will be ready soon as everything is slowed down waiting for it.

You could use an OF 4 blade head. You would still have to drill a hole in the mainshaft 28mm down from the top. I dont know if the blades would clear the top of your cabin. If they didn't, you might be able to raise the mechanics in the fuselage.

I will post some pictures of mine tomorrow. I have done more work on it, but progress has been slow due to other commitments.

The mechanics are mounted in position and the driveshaft lined up and cut to size.

Peter Wales
http://scalehelicopters.org

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07-06-2009 02:28 PM  8 years agoPost 14
Peter WalesrrElite Veteran - Orlando Fl - My Posts: All  Forum  Topic

I have cut a hole in the woodwork around the chassis to accommodate the fuel tank. Then I added a couple of pieces of scrap wood to it to help firm the tanks location

This is how the fuel tanks fit, one on each side

The tail rotor servo was fitted into its little chassis and the hole in the bulkhead widened to clear the pushrod

The tail drive was cut to length and the bearing holder fixed with some PFM. I love this stuff. It fixes very strongly, but if I want to move the holder, I can do it fairly easily.

The driveshaft comes in at a slight angle and wear on the inside of the dogbone coupler is a concern so I will keep an eye on it.

If it starts to become a problem I will tip the mechanics forward so the back end is at the right height and then reposition the bearing holder in the bulkhead.

Fixing the top of the mechanics to the fuselage is a bit of a problem and I have decided the easiest way is to brace from the servo tray to the sides. So I fitted some extra wooden supports just inside the door frame to stiffen the fuselage up.

If you fit the OF head Tromilu, it will look like this

Too low?

Peter Wales
http://scalehelicopters.org

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07-06-2009 11:58 PM  8 years agoPost 15
Tromilu

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Copenhagen - Denmark

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OF rotor head look good
I think the OF head look really nice. The clearance to the top cowling should be no problem. Since I obviously have decided to tilt my mechanic slightly more than you have I think the blade-tail clearance should be safe. My mechanic is tilted 5 degrees. I choose to lift the mechanic about 15 mm higher than the wood work from Vario would. As high as possible, just engough to have a safe clrearance between servos and the underside of the top front cowling.

Do you have experience in the diffent flight characteristics between the OF heads and the Vario heads with two blade bolt per rotorblade?
I have flown the 3 bladed Vario head with so little succes that I have invested in a Virtual Flybar System from Mikado. Hope this will make the multiblade head more enjoyable.

Regard, Troels Mikael Lund , alias Tromilu

Ps. posted a question to Jetcat, to hear if they can supply alternate main shaft lenghts! Waiting for that answer.

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07-07-2009 02:31 AM  8 years agoPost 16
Peter Wales

rrElite Veteran

Orlando Fl

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The OF head and blades fly much better than the Vario 2 bolt head and blades. the secret is in the weight of the blades. 800mm vario blades weigh 200gms, OF ones weigh 300 gms.

I use them on my ec135 turbine with no head gyros and love flying it.

Strange you say you have increase the height by 15mm to clear the servos. I have put the servos under the servo tray just to clear the cabin top. maybe the top is different in the 412 and the 212

Peter Wales
http://scalehelicopters.org

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07-07-2009 11:30 PM  8 years agoPost 17
seattle_helo

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Seattle, WA USA

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Nice work, Peter. Troels, that exhaust looks very well done. It's not easy to get the stainless in that kind of taper and shape so precisely. The craftsmanship is impressive. I'm sure Tam's will be equally impressive, though.

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08-22-2009 06:29 PM  8 years agoPost 18
bcm

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Tuolumne,CA

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any news?

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08-23-2009 02:57 AM  8 years agoPost 19
Peter Wales

rrElite Veteran

Orlando Fl

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Still waiting for the exhaust to come back from Tam

Peter Wales
http://scalehelicopters.org

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08-24-2009 09:00 PM  8 years agoPost 20
Tromilu

rrNovice

Copenhagen - Denmark

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work still in progress
My work on the PHT2 in the Bell 412 fuselage is slowing down due to vacation, but now the speed is up again.
Realized that the OF head will not fitt the 412 top cowling, but only the 212 cowling(See picture in Peters reply).

I have decided to go for a 2 blade configuration until a suitable solution pops up. Rumours says that Vario is having the same problem for their soon to come Bell 412 for PHT2 kit. Looking forward to see that layout.

My model is now wood-finish. All frames and stringers is done and the problem about stabilization of the mechanics in the top is solved by making additional frames in front of the sliding doors and alumnium brackets from the servo console to the top sides. I used 2024-T3 Aircraft aluminium to avoid too much weight. (Got to get this model under 8 kg. - I hope).
Electrical power is now decided to be 2 LiPo packs controlled by a PowerBox Gemini unit. This little nice thing supply 5 volt for my four analog Futaba 9202 servos for the swash plate and 6 volt to the tail servo.

I my quest for easy serviceablity I cut a door opening in the nose section - allowing access to all charging plug and LiPo ballancer sockets.
My theory is that if my models is allowing very easy servicing and easy access to all components the general safety of the model is much improved. If components is not easilly accessable one might not be as motivated to inspect and clean the component as frequently as it should be.
For that reason I have installed all components, fuelpump, filters, ECU, fuels valves, radio receiver, gyro and so on, behind panels attached with maximum 4 hex screws. Looking in to the cabin, no RC equipment is visable. Everything is going below the floor, including the fuel tanks.
Well, the starter battery and the two receiver packes is above the floor, but are positioned in racks in the nose dome. The newly cut door is hinged with hidden hinges and facilitates primary access to the batteries and the PowerBox solid state on-off switches.

The collector tank (hopper tank) is a standard Vario 540 ml. kerosine tank installed just aft of the mechanics, below the tail rotor shaft.

Got to find a way to let the sliding door work nicely. Don´t like the sliding rails Vario is suggesting, but s leaning more to the idea of using powerfull magnetos.

Anybody having experience in using magnetos?

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HelicopterTurbine Helicopters › PHT2 in a 212
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