Gazzer

I had the near ultimate thrill last night when I ran my new Wren MW 54 MKIII kit for the first time.

not only was it the engines first time, but it was my first turbine and so the whole thing was completely new. The build of the engine took a measly 4 hours, and I had two small issues which I managed to sort.

I spent 1/2 putting a test platform together, an hour running in the pump and last night, with two of my mates, we gave it a go.

At first, although you could hear the gas ignite and see some heat haze, the pump would not start....... Quick investigation revealed the thermocouple was not pushed fully home, I must have caught the cable.

Although I had checked the data terminal I had been silly and on seeing 0 deg because it was not running, it would be OK, but of course it should have shown ambient temperature. Plugged home and 108 dg showed. Alan fed some air via an electric motor and prop and the temperature cooled down.

2nd attempt, pop went the gas and then off it went. Wow, it speeded up quite quickly making the loudest and most fantastic whoosh I have ever heard. It idled at around 45k, it was hunting just a little, but no great issues. After a minute I raised the stick and took her to 80k. 2 minutes later I raised her again to 100k and all 3 of us backed away from the engine!!!! I suddenly realises I could not be frightened so calmed my nerves and went back to the stand and checked out the data, 580 deg at 100k.

I did a bit of throttling very gently and after a total of 6 minutes throttled back and stopped. During the cooling phase the bendix stuck but we quickly freed this and all was quiet and cool in about 5 minutes.

I had used about 800ml of fuel.

Replenish the tank, top the batteries, POP, away she went again. Idle was a little smoother with just a tiny bit of hunting, and after a few minutes at 100k, time to go flat out. Wey hey!!!!!

I had noted just a little burning coming from the plug, and had tightened it between starts, but it was still there. Close inspection seemed that it was not coming from the engine but the glow plug connector. 8 minutes of running with gentle throttling and one full out slam, had the engine performing flawlessly and I was quite impressed with the speed of throttling. Time to stop as the clunk in the coke bottle tank was just beginning to poke up through the fuel (the bottle was horizontal).

The noise was phenomenal I had not appreciated just how loud. The smoothness was mindblowing. At 160k, the fuel in the coke bottle was like a mill pond, touching the stand or the engine case belied what was happening underneath.

So folks, I did it, easily and simply with only my own research and knowledge and watching a few turbines at shows etc. That I think demonstrates how well the products are now set up and supplied.

To all the guys and girls at Wren, thank you, a superlative products that does what it says on the tin!!!

I want to buy another one already!!!

Gazzer

scubyfan

Good to hear your jet got to a flying start! (pun intended)

I am inferring that this was the kit? I have been thinking about buying it, as it is at a good price, but worry about balancing issues. Did you balance the compressor/turbine or did you just put them together out of the box?

Good luck with your turbine! I hope to join the elite club real soon.

Gazzer

Hi Scuby,

This was a kit the latest MkIII which is good for at least 14lbs.

I too had the concerns over the balancing, but this version comes pre balanced. I fyou look at the compressor and turbine wheels you can see some balancing grinds. The turbine wheels is pre mounted and bolted to the shaft, so providing you don't undo it, it is perfectly in balance. I believe Wren use a pretty sophisticated balancer at the factory to provide this component ready to go.

Thus, this was absolutely straight out of the box and I had no balancing to do myself. At this price, putting it together yourself also helps you understand how they work, and for future servicing etc, will mean I can do it myself. If however, I ever need to remove the turbine wheel, then I would return that and the shaft for balancing to the factory.

Building the kit was quite fun and incredible how it all just went together as it should. Stop thinking, go buy, I am sure you will not be dissapointed!!! Good luck and thanks for your kind wishes,

Gazzer

FalconWings

My Feedback: (57)

Oh men, you just pushed me over the edge.

Om getting onw of those!

As I was reading your posting, I felt as if it was me doing the first run. Im pumped.

thanks for your report Gazzer.

David

Gazzer

Falcon wings,

Thanks for your kind words.

I have been running around on a high today and only just managed not to tell my secretary (she usually gives me the look my wife does.....).

I am new to this game but this was the kind of introduction that I did not expect, I genuinely thought it would be harder.

My two mates who were with me summed it up too, we just looked at each other and went "Wow, get that!!".

I hopefully will be doing some thrust tests in the near future and will also be looking at the settings on the ECU but for now, it works perfectly and I hope to take it down to our non turbine field (way too small for jets and it is also in the middle of crop fields!!!) to show the rest of the guys.

Go get one, you wont be dissappointed!!

Gazzer

KHORTON

My Feedback: (1)

good job, what airframe you planning to use? I'm sure you will enjoy.

Gazzer

hi Khorton,

I have a BVM T-33 the new AFS version as the final power plant. It should be well suited. However, I am looking for a "mule" to have an airborne go to start with but have now kind of run out of budget!!!

I have a semi kit of the Folland Gnat originally designed for D/F and in any case it is a second kit with the worlds most awful join but it would need to have quite a bit of updating and plenty of strengthening to get it right. I can get some help for this, but am wondering if it is the right thing to do.

If someone is clearing out something old and unloved...........................

Have to say though your right, I am already enjoying and want to go and run it again!!!

Gazzer

Shok

My Feedback: (28)

David are you coming out the the jet rally this weekend?

Come find me and my AV8R.
Let me show you how great life can be without a starting wand and nitro! lol

Gazzer

Shoks right David,

twist the gas valve, advance trim, advance throttle stick and retard, watch the action.......... Pop(gas).whizzzzz (starter motor), WHOOOOSSSH (kerosene burn) crack, crack, crack( ear to ear grin as all the wrinkles straighten out on your face!!!!!)

But don't forget the ear defenders, processing air is at volume!!!

Hope you have a great jet rally this weekend guys.

Gazzer

Shok

My Feedback: (28)

hahaha heck I don't even do that much.
I just run the throttle stick to full and back 3 times and watch the magick happen

Gazzer

So I have room for improvement? Be gentle with me, it was my first time..............!!!!!!!!!!!!!!

Gazzer

Shok

My Feedback: (28)

Gazzer, does the Wren have an onboard propane start option?

Gazzer

Shok,

You get two flow solenoids with the auto start package one for gas and one for kerosene. So long as you have a gas tank then you can have it on board, as the solenoid will close to the gas once started..

I am not planning to do this in order to save a little weight. The only reason for me turning the gas tap is the bore of the tube from the gas bottle valve to the engine gas tube iss a little wider than I would have wanted and the gas tube is not as snug a fit as it should be. I have two layers of tube over the join and two tie wraps to ensure no leakage but I don't yet trust it.

Once I resolve this then the gas can be turned on and left on during engine running. I guess to charge an on board tank you would do the same,

I will have look at the Wren site to see if they provide a tank, but I am guessing those in use by other engines manufacturers would be just as good.

A quick release valve is another way of doing it and the way I will do it for the model (when I get round to building it!!!!).

Gazzer

Shok

My Feedback: (28)

yeah Im sure you can just order the CO2 cartridge and festo check valve from anyone, it really weighs nothing. I just plug it into the powermax can to fill right before starting.

Gazzer

Shok,

You can tell I am new to this....

So an empty C02 bottle like the ones they use for Soda syphons, and a festo check valve, fill it from your main bottle and on board system you have. Cool.

I have heard that some systems vent the excess gas off, presumably with the above you would land with what you take off with, unless you have an, er, mishap!!! I am guessing that the Co2 cartridge is pretty robust though?

Gazzer

scale dail

My Feedback: (8)

This is just the stuff i need to hear! I have both a jetcat P-60 or Wren 54mkIII on order,but I think the Wren is going to be the one. waiting for either ether one to arrive is killing me!

Shok

My Feedback: (28)

Gazzer, let me grab my camera and I will take a picture of my birds nest lol

Gordon Mc

My Feedback: (11)

Just be aware that the thick walled CO2 style cartridges retain the cold more than the thin-walled ones that e.g. Jetcat provide. On my RAM 500 this used to be a problem, because the start gas would not atomize as well when the container was helping to keep it freezing cold. You actually used to be able to spot the RAM 500 owners in our club because they would be the ones doing the left-handed massage of the CO2 bottle, trying to keep it at a reasonable temperature while trying to start the engine (This hand-warming procedure was a tip from TonyF BTW, before he came up with the idea of just ditching the CO2 cannister and using the thinner-walled jetcat style tank.)

Gordon

Gazzer

Scale dail,

I was in the same dilemma with whether to get a P70 or the MKIII. Wren were very honest about some delays in kit production and I was that close to ordering a P70. The Jetcat USA boys were really helpful too and I respect them wholeheartedly for their speed of return to questions and honesty, and they were nice about it even when I went to Wren I still had some hints about the BVM T-33 landing techniques!

I can't compare the engines that would be wrong, but I am very pleased that I stayed with the Wren. Being a self assembly kit (build is overkill) I understand what the bits are so future costs for servicing will be lower, it was quite fun to put it together and then given that this is my first turbine and no one with experience was to hand, it all worked perfectly. That is quite some reputation to have in my view!!!

The other side of the coin was the economics, this version is about 1/4 cheaper than the P70 and on board it will be a bit lighter, as the model I have chosen could do with a bit of oommpphhh or whooooooossssssssshhhhhhhhh as it sounds, it became the best value for me.

Let me know what you decide on!

Gazzer

Shok

My Feedback: (28)

here ya go,

Gazzer

Gordon,

Thanks, one could interpret the hand shake with RAM owners being synonymous with a particular gesticulation!!!!! Joke honestly!

Shok,

Thanks, that will be interesting.

Gazzer

Gazzer

Shok,

Your a bit nimble with the photo's and labels too!!!

Makes it nice and clear though, thanks. I am sure this would work with the Wren. I will get hold of a check valve, filler valve and t piece (C02 case too) and give it a go in the next few weeks and report back.

That was really kind of you to go and do, time when you could have been building or flying. Much appreciated!!

BTW what aircraft is it, was that really balsa I saw!!!!!

Gazzer

Shok

My Feedback: (28)

thats my PCM AV8R, no fiberglass on this one, thank goodness because I have had some serious landing incidents learning to deal with landing a turbine.

Gazzer

I've just had an email from Wren and they do provide an on board gas tank. Could not see it on the site but I know it will be there somewhere!!

Might try that option instead of the Co2 bottle.

I will think on and let you know!!!

Gazzer

PS Shok AV8R looks cool, I too worried about landing, the mandatory part of flying!!!!!

FalconWings

My Feedback: (57)

[/quote]


David are you coming out the the jet rally this weekend?

Come find me and my AV8R.
Let me show you how great life can be without a starting wand and nitro! lol
[/quote]

Ronnie,

I will try to make it, but Im trying to spend every free hour that I have working on my Agressor and my Falcon, so that I can join you guys and fly with you guys in the future.

The Agressor will be for my Turbine Waiver, and the Falcon will most likely have a Wren 54 in it (thanks in part to this post). So as you can see, I have a plan.

Meanwhile its hot-melting wands, glow plugs, 3 minute flights and expensive glow fuel for me.

C U soon.

David