Cermark F16 Turbine Build

[winchweight]

Hi guys and gals. I have finally made a start on my budget F16 build. I say budget, I want a turbine but don't want to pay through the nose. Also I want a scale model not another Wot4 / Baby Boomer etc. I am very fortunate in having a friendly LHS who gives me a good club discount as well, but these items still cost the earth anyway.

So, I have bought a Cermark F16 turbine kit, a very comprehensive it that comes with air/air retracts, brakes, fuel tanks, all the valves and plumbing for the brakes and retracts, jet pipe and all the other clevises etc you'd expect from an ARTF.

I am fitting a Mk2 Wren MW54 that I bought from eBay for £500. It came with all the gubbins for a manual start, and Sarah at Wren knew the engine well so the history was sound.

So tonight I started out. The model is superb, a glossy gel coat with the USAF Thunderbirds display team colours. It's also huge! As seen here in my workshop:

I began with the nose gear installation. the manual is pretty vague and begins with the wings etc, but I don't want to keep removing these when turning the fuselage over etc, so I began on the fuselage.

The gear is excellent, but on a tip from an mate, I removed every screw and thread locked them (glad I did 'cos some were very loose).

To get the oleo cylinder in you have to let out the hole, which is hard because the cylinder is tight between the intake for the engine and the fuselage. You also have to make a space to get the airline connectors in.

Luckily the interior of the fuselage is spacious because the nosewheel steering servo in beneath the ducting!

Amyway, this took langer than expected, so I have to leave the fitting until tomorrow (when I have bought some more wood screws and some quick connectors).

Here's my Black Horse Mohawk BTW. Very tail heavy, so I fitted a seperate rx nimh instead of feeding it off the lipo, and fitted the battery right up against the cockpit to help with the cofg. Next I intend fitting external stores and repainting it!

That's all for tonight.

[David Ashby - Moderator]

Wow, quite a workshop you have there Shaun. Can't offer any advice as you're well outside my knowledge sphere with jets but will be following with interest.

[winchweight]

Thats only about a quarter of it (the workshop) and an upstairs, it was built to my spec. There's a Jag XJ8 in the other side and behind the camera there's another work bench and a freezer. 

The model is being built on a door BTW, that gives you an idea about the size.

[winchweight]

Ok, moving on. I fitted the nosewheel steering servo (HiTec 645MG) with a 12" extension.

 I have fitted some eze connectors to the nosewheel steering tiller arms, and as a result I had to shave a bit off the mounting plate to clear them.

Not forgetting to fit the airline first. I am a little worried that they might be a bit pinched up front though. We'll see.

The mains went on easily (I am using cap head wood screws from model fixings)

And then, she was ready to stand on her own feet!

Slight problem with toe out on the main wheels though. The allen key required to undo the wheel hubs is bizarre! Possibly a 2.4mm fastner. I have ordered one, so we'll see.

And then a dry fit of all the major airframe components.

More soon!

[Tim Mackey]

Hi Shaun, nice blog and even nicer model! Always loved the F16.

I am jealous, having decided since retiring that my policy is not to own and fly anything that I can not afford to lose, the prospect of me ever going turbine jet is very unlikely - will have to borrow yours

[winchweight]

Well I have to say, I don't think I can afford to lose this, but as it's not new money, i.e. it's the proceeds of sales of other models, then it's not the same (I hope...).

[Tim Mackey]

Still money to me mate, and money that I could well have spent on something more necessary - dont get me wrong I love the whole idea, but just cant afford that sort of disposable income - especially as I frequently remind the wife what a waste of money her £1 aweek on the lottery is

Most of my modelling money is either "earned" seperately or funded by sale of other stuff too, but its still a heck of a lot of dosh to potentially lose in seconds.....

[winchweight]

I try not to think about it.......................................................................

[Tim Mackey]

BTW the odd size allen key may be imperial sized - the springair retract stuff in my Spitfire uses imperial - found a set down in my local hardware store. I advise you check this first, as if you try to useone of slightly the wrong fit, you will chew up the socket head and then your stuffed!

I guess you know this, but just trying to help.

PS funny isnt it that the yanks couldnt wait to kick us out of the place and start their own side language etc, yet they keep good 'ol imperial measurements in their engineering !

PS - this was very tempting  when I was browsing around earlier this morning Hawk

just checked back now to get the link in the posting and its SOLD ( no not to me )

[winchweight]

Cheers Tim. Yes I had thought about imperial. I have ordered a 2.4mm allen key (whatever that is in imperial).

You should have bought it.... you know you want one...

[winchweight]

Ok and update.

I got an imperial allen key set and it appears I will need them as all the screws are imperial sizes (God bless America!) This has allowed me to straighten up the wheel and now the airframe rolls superbly along the ground.

Next I set about fitting the elevator servos. They are designed to sit on alloy 'T' pieces, which are in turn screwed down to ply bearers, which are then to be epoxied to the airframe.

Problem 1. The servos et al don't fit into the servo bays. So this necessitates huge amounts of thinning down and dremelling out to get them in.

Problem 2. Once in the bay, it is impossible to reach the screws to attach the servo (via the T piece) to the bearer.

Problem 3. The supplied screws are too long and protrude through the T piece, preventing the bearers fitting snuggly up against them.

As stated much use of the dremel was required. The servo is screwed to the bearer and will have to be glued, (servo, bearer and T pieces) in one lump into the airframe. And finally the supplied screws were ditched and cap head, shorter screws and washers fitted.

The elevators are then fitted through nylon bearings and are retained with nice alloy cams which will in turn connect to the servo. The supporting rod is supported either side of the cam by a nylon bearing

I have also selected a pilot, a 1/6th Red Arrows pilot from Pete's Pilots

And painted the avionics tray to ensure it is fuel proof.

Finally, if you are considering building this model, be warned the gel coat finish is very, very fragile

[winchweight]

Arrgghhhhhh!!!!!

What a PITA! I fitted the servos exactly as described (and shown) in the pic in the manual. But it would seem the pics show the servos installed back to front and now my servos foul on the bay covers.

Well, it's too late to do anything about it because now the whole lot is installed and it will be a massive drama removing it, so it's staying.

All I can see is that over time a slot will wear in the cover where the servo arm is contacting it, but seeing as the cover is thin it's not causing any undue stress to the powerful servo,  I'll live with it for now and in time make a modified cover to suit.

On the upside, the servo in the fin is fitted and the fin is on!

[Tim Mackey]

Dont you just hate it when that sort of hing happens - take your time and follow everything to the letter and they screw up ! ARrrgh indeed. Maybe you should make the small slit in the cover yourself rather than let the servo do the job which will as you say, put an extra strain on things.

Gosh those main wheels dont look too far apart do they - I know its scale, but I bet she will wobble around a bit if the landings are not nice and level....sorry, didnt mean to add to the pre flight nerves there winchy

[winchweight]

Apparently it's a luvverly model to land. Great low speed handling so you can plonk in down gracefully.

What I've done is thin the covers until they're paper thin, I can now see the track of the servo arm and will as you say, open it up a little. I might have a go at making some new covers later, as they are only vacform jobbies.

I took delivery of my air valve today, it's a Jetronics Dual J valve, which is electronic and designed for air up / air down u/c systems. I will eventually add a failsafe which drops the gear if the pressure drops.

I also received a Dubro gas fuelling valve, which I beleive is suited to kerosene. Anyone able to confirm this?

[winchweight]

Right then. I spent a couple of hours trying to sort out the elevator servos, which I have now done. But and it's a big but, I have too much play on the clevises. One of the supplied ones broke and I have used a set of Pete tindal clevises, but the pin is too small and there's loads of play on the elevators.

Can anyone suggest a supplier of beefier clevises please?

[Dusty]

Shaun, that looks awesome, nice workshop too! Nice xmas pressie!

[Dave Towell]

      Great looking model!!  I hope it all goes well from now on and no more little problems. You think in this high speed digital age that they would get thing right and update the "instructions/destruction's". it's interesting to know that these problems are spread across the whole price spectrum. (and there was me thinking that the modeling manufacturers had it in for just me!!!!)

Thanks for sharing this with us will have to keep an eye on this thread. good luck and hope all goes well!!

[winchweight]

Loads more done today. Update tomorrow!

thanks for the support!

[winchweight]

RIGHT!!!! I have been a bit lax on updating this thread as I have been a bit busy with other stuff lately. However, the build has been progressing steadily.

The elevator clevises are still an issue, but I hope to have a solution. I have removed the pins from the clevises and intend using 2.5mm caphead bolt and nylock nuts instead. Hopefully this will stop some of the play, we'll see.

The retracts are in and tested now, along with the electronic valve and air tank, as is the brake valve, but that is as yet untested. Just one issue to be resolved here, the nosewheel steering wires are stopping the nose leg extanding fully as they snarl up on the fuselage and are a bit too tight as well. I have a plan for that and should sort it over the next week or so. (Pics will follow).

Just a note: the retract / brake valves are the Jet-Tronic valves and they sit quite high if mounted on top of the radio deck. There is a risk of the cockpit floor pressing on the valve buttons, so to counter this, I have mounted them on rails from below, protruding through the deck. (You've guessed it, pics to follow)

All the servos are now installed, and just need the pushrods connecting up. I have opted for a Spektrum AR9100 rx and 3 remote aerials at different points around the fuselage. I have two 2300mah nimh battery packs on order from Vapextech to power the system and to afford dual redundency. (Again with the pics)

I have also test run the engine on the bench and it topped out at 160,500 rpm and made a hell of a lot of noise

Another detail I have been working on from time to time:

Remember him?

Well here he is now, resplendant in his hand painted Thunderbirds scheme. I know he has the UK pattern helmet etc, but I love Pete's Pilots figures and it was the closest he had.

 

I am particularly pleased with the T'Birds logo on the neck of his t-shirt.

Anyway, enough for now. I will try and get the photos updated tomorrow.

[Tim Mackey]

nice artwork Shaun... looking forward to the other pictures, and the post flight report of course !

[nigel sheffield]

looking really good

Iwould love to built something like this but don't have space, or money or somewhere to fly it.

I'll be watching you do instead.

[winchweight]

Ok, as promised, some photos.

The nosewheel steering used to foul on the wires, so I have added some elsatic bands to pull the wires out of the way, I've reduced the tension on the wires too and taken the corners off the nosewheel bay.

The mains and the piping for the wheel brakes. The tie-wraps have been replaced with Tamjets brake pipe clips.

The recessed air valves

The new and improved elevator linkages. The original clevises with the roll pins removed and replaced with 2.5mm bolts and nylok nuts, and Pete Tindal clevises on the servo horn. Much less slop now.

That's it for today, tomorrow the brakes test and the fuel system moves on!

[David Ashby - Moderator]

How's the jet coming along Shaun?

No one said you could have a rest you know

[winchweight]

Hi David. I really need to inject some enthusiasm into this. I had a few problems with 2 broken Jet-tronics valves (£75 each!) and air leaks that changed on a daily basis.

Hopefully my valves are on their way home and fixed, so I should be able to move on.

 

An update will follow soon.

[winchweight]

Well, things have moved on. The jet is finished all bar the last bit of fettling, and ready for ground tests this weekend.

Jetronics were great and the valves were repaired and returned within 10 days.

 

Then the retracts themselves stopped working, due to a seized trunion bearing.

 

Engine ground runs went well apart from flooding the engine as i forgot to shut off the fuel line to the donk, so as I fuelled it was pouring into the combustion chamber. Luckily I spotted it before the start though!

 

Fuel system is now leak free after I threw away the Overlaner T pieces and replaced them with Festo ones. All the fuel lines are shortened and the whole system was fitted into the model.

 

Then the jet pipe mounts sheared off. Lightweight (1mm) stainless is a pig to drill and impossible to get welded. So a new piece of stainless was grafted on and crimped to the original lugs.

 

The avionics dropped straight in without a drama, although the whole model is a bit nose heavy.

 

I'll take a few photos later on.

 

Things to do (assuming nothing extra is thrown up by this weekends testing).

 

1) Replace the aileron clevises with metal ones.

2) Adjust the travel of the flying surfaces.

3) Secure the batteries, rx and air trap.

4) Repair the aerial lead for the remote aerial in the tail of the jet (a wire pulled out of the plug). There are 4 remotes and one control box (Spektrum AR9100 power safe)

5) Make some elevator servo covers as those supplied impinge on the servo horns.

6) Fit the u/c fail safe (Gear Sentry)

7) Check operation of the throttle failsafe.

8) Replace the brakes air reservoir with a bigger one.

9) Weight model.

10) Final security and functional checks.

 

Then begin drinking heavily as model is test flown by club jet guru.... (next weekend hopefully)