TN Retro Jet 75

[Djay]

I received my plan and wood pack from Tony Nijhuis today to build the Retrojet 75 Jet trainer.

The package weighed in at 8.5 kilos so will be interested to see what has been sent when I get home from work.

Shipping from UK to Dubai worked out at just over 100 pounds.

I have an old Jet Joe 1800 turbine that I had rebuilt years ago and never used. As I have G booster and Jet Central turbines I thought that rather than leave this engine laying around never going to be used, I would build a club trainer as most people at our club are more than proficient to fly it.and have some fun.

Plus I love building the TN designs as they build so easily and fly so well.

I will see if I can get a build blog going if I remenber to take photos.

Please feel free to join in if anyone else is building one.

When I get home my TF sea Fury and TF P39 will have to be evictided from the build benches and put on hold whilst I build this.

Darryl

[Djay]

Well got home and opened the package. mostly pre cut ply with lots of 4 ft sheets of balsa wood. But no plan or vac pack, so no building for a while. Darryl

[Djay]

Got the plan and nose cone delivered today.

Within 5 minutes the build had started with cleaning up the cnc wood parts and gluing the fuse doublers on.

The wood package, 8.5 kilos.

some of the fuse cnc cut plywood parts with a 24 inch ruler for reference.

with the Jet Joe engine.

This engine is over 7 years old and I am at least the 4th or 5th owner. It was in a Boomerang Intro I brought which had done the rounds out here as a jet trainer, and despite what people say about these engines, the engine has performed perfectly every flight. It recently had a rebuild/overhaul and not been used since, so needs a home.

All the cnc cut parts are perfect and really good quality as expected.

anybody building this recommend the servos to use?

More pics once the weights are removed from the drying parts.

Darryl

[Major]

Hi Djay!

The kit itself looks awesome! Good luck with your build, I shall follow with intrest!!

Has anybody seen it flying?

[Djay]

the build is progressing well, and all the parts are so far going together with no real problems.

sides are joined and doublers started to be added.

first formers in place.

sides ready for joining.

sides joined.

only reason it is taking so long is I am using white glue and 30 min epoxy, so each stage I have to wait for the glue to set, otherwise fuse would be finished it is that easy to assemble.

One problem I have noticed is the fuse is very narrow, and the engine mounts are fine for the small lower end turbines, but as mine is an 18lb thrust turbine, and of an old design, it is a lot fatter and will not fit between the engine bearers or through the hole in the bulkhead, so when all is together and the glue has set it will be out with the dremel. Anyone planning to fit a P80 may also have this problem.

Glue should be dry from the next stage so back to the work bench.

Darryl

[Djay]

progress marches on.

with my helper.

nose done

rear formers

all parts are pre-cut and fit perfectly.

it is a big aeroplane but so easy to build. I have been out most of the day otherwise the fuse would have been finished.Went out and brought a 50 oz and 24 oz fuel tanks, a heavy duty moulded u/c, wheels and gas fuel tank stoppers today.and some more glue

As we are 4 hours ahead of UK , finished for the day and now going to watch the footy. building resumes tomorrow after work.

Darryl

[David Ashby - Moderator]

Good stuff Daryl, coming on fast, I'll be following too.

[Djay]

The build progresses.

Darryl.

[Major]

Thanks for pics Darryl.

I don't know why, but |I was sure that construction of turbine-powered aircraft has to be much tougher than typical IC plane and much more complicated, but this one looks very easy to build. Your thread makes me want one, with Wren 75 Jubilee.... ehhh, wishes....

Cheers

Tom

[Djay]

Thanks Tom.

I think some kit manufacturers could learn a lesson from Tony, as to how to cut out parts and make up a kit. His designs and cnc/wood packs always go together so well.

Tail is finished, as they are just sheet wood.

U/c has been mounted just to try it all for fitment. The nose gear is an issue as it needs to be strong, so will be ordering the purpose built one from TN later this week.

Just planning the layout inside. The plan shows a 60 oz tank, but I think it should be 50 oz, as this is the biggest I could get and it is the same size as drawn on the plan. The header tank is shown as a 20 oz, but I will be fitting two 24 oz under the main tank just because there is so much room available.. Pump will go above the twin tanks and the ECU, R./X and batteries will all go in the front compartment and be lost inside the cavernous area.

The engine bearers have been trimmed and I had to cut away most of the main bulkhead to allow the engine to pass through, so will reinforce this later, though there is no stress or forces acting on this part from the engine.

All in all I am enjoying building this as basically all the parts just slot together with no cutting or trimming.

As I only get an hour a day during the working week to build it will slow down a bit, but hope to start on the wings tomorrow or next day.

Darryl

[Djay]

wings started

start of the wing build

less than 10 minutes later wing structure is finished.

Darryl

[Bucksboy]

I doubt if I'll ever build one but I'm really interested to watch your build. I've built several TN designs, I agree with you about his designs being easy to build.

Good luck

Bucks.

[Djay]

Hi Bucks.

nice to know someone is looking at this thread.

To be honest expected a few more people to show an interest, as I am sure many people are, or want to build one of these.

Unless you have good wood working equipment, you must buy the cnc pack, as large amounts of the wood are 6mm ply cut out with slots, holes etc.

Other wing half is built, just got to sand them both and start the sheeting before joining them.

All the tail parts are built, just require sanding to shape and then fitting to the fuse.

Once that is done the remaining tail boom sheeting will be fitted, then the fuse is ready for sanding and covering.

Hope to have a good hit at it this coming weekend as the wife is going away.

my plan is to finish the fuse so I can mount the engine and test run it before completing the rest.

Darryl

[Andy Green]

I too am building one (for a client so as its not mine I'll not be doing a build blog on here) but will be watching yours.

For info I have a build blog on my web site.

Andy

[Djay]

Hi Andy.

What turbine are you installing in yours?

Hope it fits better than mine does. This plane is really made for the new generation of lightweight smaller diameter turbines, not the older ones.

I have a problem in that not only is the turbine to wide for the bearers but the fuel pie, egt probe, RPM lead and gas pipe poke out from the turbine case and prevent it passing through the main bulkhead.

It will be overcome but the actual engine fixing into position will have to wait untill all is finished, so it can be moved back or forwards to adjust the C of G.

You could literally build this a/c in a weekend.

Darryl

[Andy Green]

To be honest Darryl I dont know. This is a build for someone else. I'm just building the airframe to plan upto the covering stage.

This is why I'll not be doing a build blog on this site. It doesn't feel right as its a 'commercial' build

Happy to share experiences, and totally agree with comments about TN and his ability to produce a slot together kit of parts.

Andy

[Djay]

Appart from the bearer spacing, the plane is nearly finished and I have had no issues or head scratching moments, in fact I have hardly even looked at the plan throughout the build.

Thats something to mention, the plans are on 2 sheets which are each about 2 meters long, so you need a big workshop to unroll them in.

I have just ordered the nose wheel assy and a set of metal hub wheels from TN, so hopefully they will arrive by the weekend.

Will probably cover the model in solarfilm, as I have massess of the stuff laying around, but due to its size it may well turn out a bit multi coloured.

I have a load of very thin lithoplate which I will line the engine bay with, as it is an akward area to cover.

Darryl

[Djay]

Build is progressing nicely.

Tail sections, hinged but need final sanding to shape.

Top of wings sheeted.

wing halfs joined.

It really needs to be a two piece wing, but it is so difficult for me to obtain the parts needed that I went with the one piece as designed.

Just making the tail servo mounts and then fit the pushrods so I can then close of the top of the tail boom, and fit the tailplane.

Darryl

[Djay]

More progress today.

servos installed. Sullivan heavy duty black push rods for elevator, closed loop for rudder.

Tank supports.

fuse build complete.

tanks , upper 50 oz, lower 24 oz, plus I have a spare UAT so that will be installed to give that little extra capacity.

Just a good sanding and fuse will be ready to cover.

Wing lower skins made but had enough building so will install those during the week.

Darryl

[Wez]

Hi Djay , you are doing a great job with the build , following with interest

I am having this kit built for me ( various reasons ) the kit has been designed

around a Wren 75 jubilee ( now re-named Wren 80 jubilee).

this is what i will be installing in mine, should drop straight in , its my

first jet turbine should be fun.

Wez

[Djay]

hi, Wez.

hope you enjoy flying it once it is all complete.

my first and current jet is a Boomerang Sprint. it is so easy to fly and enjoyable.

I had a Skymaster Hawk, but that came to grief.

this one will be just to use the spare engine, and hopefully it will fire up and run ok, otherwise I will have to wait untill my Boomer comes to an end and fit the G Booster from that into the retro Jet.

Lower wings all skinned, UAT tank holder made, inside of fuse has been painted green, as this was the only fuel proof spray paint I had available.

next stage is wing L/E and T/E's then flaps and ailerons.

Darryl

[Djay]

work is progressing slowly but surely.

inside of fuse has been fuel proofed, but I only had green spectrum fuel proof spray paint handy. Mount for UAT made and fitted.

Wing progressing.

Just some of the covering materials left over I will be able to choose from. Will be using Solartex as not enough shiny film and can not be bothered to glass the model.

using the scraps I had left over this is what I ended up with, not quite what I wanted but I went for visibility, and these colours show up the best against our blue skies. Still some bits left to cover.It is a large plane to cover.

now covering the flight controls and installing servos, then start the install of all the internal fittings and fuel system etc.

Darryl

[Djay]

All the flight controls except the ailerons are fitted in place, dry fitted the tanks, valves, ECU, pump etc, and trial fitted the motor.

With two heavy LiPo's sticking into the nose cone it still needs 2 lb of lead in the nose to get it on the C of G.

The engine is as far forward as I can get it and more forward then shown on the plan.So if you do build this you will need the lightest turbine you can get hold off.

Still with its massive wing it should not be a problem with the extra weight, and I will probably add a 3rd LiPo as a back up instead of carrying dead weight. I will also build an extension in front of the fwd bulkhead protruding into the nose cone to put the lead on, so it will be about 2 inches more forward of where it is placed .

Now have to get the enthusiasm to make all the power leads for the turbine and pump.

Darryl

[Djay]

Made a ply extension in the nose for the batteries and lead to sit on.

All power cables and engine cables are made, fuel system components are ready to final install.

The problem is, even without any fittings at all inside the aircraft, it is massivley tail heavy, and the turbine sits aft of the C of G. So to get the balance right is not going to be easy., Most parts are as far forward as possble, except the tanks, which remain over the C of G area.

Going to clean the inside of any debris and final install everything tonight, which just leaves the servo hook ups and ailerons to be final installed.

Darryl

[Djay]

engine mount area.

U/C temp bolted on.

Engine mounted.

nose extension with temp lead weight to hold nose down while I work on it.