felker14

My Feedback: (50)

Look what UPS dropped off today. Thanks Wren USA.
I'll add more pictures after work.

Eddie P

My Feedback: (4)

The numbers are just fantastic on this Wren 100. 22 pounds of thrust on the same weight as a Supersport. The thing that impresses me most about my Supersport is the miserly fuel burn, however, at the thrust it's putting out. No favors are made with a small can, big thrust engine when we have to carry gallons of fuel to feed an overly thirsty engine. Sure, much of the math in thrust generation is converting fuel to efflux energy but its nice to have an efficient system to start with. I hope the Wren 100 is as good on fuel burn as the Supersport (I bet it's pretty good).

Nice job guys! Looking forward to hearing and seeing this engine in person some day soon.

felker14

My Feedback: (50)

Here are #'s Ron got from Wren USA open house

"Results from fuel tests:

Conditions:
29.44 pressure
32.5 dew point
800 ASL
72 F.
5% Mobile DTE light in kero

160,000 RPM
12 ounces / min
52psi fuel pressure
740 C.
21.1 pounds thrust

130,000 RPM
7.75 ounces / min
30psi fuel pressure
558 C.
11.2 pounds thrust

110,000 RPM
5.5 ounces / min
18psi fuel pressure
510 C.
7.1 pounds thrust

These tests were performed during our open house 10-16-2010 by the guests, and witnessed by all in attendance."

I do think this motor will be winner.

felker14

My Feedback: (50)

Here are some more photos. Then plan is to sell Gold in photo and purchase either JMP Hustler or Comp-Arf Flash for this engine. Leaning torward Hustler do to fact JMP is only 25 minutes away and thinking a Hustler would fun with this small little power house. The only thing missing is engine mounting straps. Ron has them on way to me. Hoping to run this weekend and post video. Engine could go on Nano until Hustler is purchased.

gooseF22

its all I can do not to drop one in my nano..... it flies great with the MK3 at 14lb though... probably rip the wings off

gooseF22

I was on the controls for those consumption tests...we used a 3300MAH battery for the fuel pump. I would suggest a good strong lipo because you are making over 50psi on the pump. that will take some power. what we didn't do was check the current at WOT, but will try to do that sometime soon. And yes, for those that ask, its the flightworks 200 pump and a Xicoy ECU. Its a very sweet setup. the Xicoy can run the new Wren mini plug, which works excellent. Very positive starts.. better than any standard glow plug I have ever seen.

Its an outstanding successor to the super sport. It should power any 20lb class model and save you weight , fuel weight, and such...

thanks for letting us play with the new motor Ron!! you have a winner here..

joeflyer

My Feedback: (48)

Did Wren upsize the fuel line from 3 mm. to 4 mm. when going from the Supersport to the 100? It seems that would be a better way to go than over stressing the fuel pump.

Eddie P

My Feedback: (4)

Yes, it would even help with standardized fuel fittings too, in addition to higher volume for the pump.

Jim Cattanach

The Wren 160 only has a 3mm fuel line. I had some concerns when I saw it, but it gets enough fuel.

Xairflyer

My Feedback: (1)

Yes seen that on the wren 160 in the Airworld L39 I was working on recently, there must be a reason why wren stay with 3mm pipe, 4mm is much easier for fitting to valves, pumps filters etc. I tend to do everything with 4mm then change to 3mm just beofre the turbine.

BaldEagel

Probably the same reason thay have not introduced Kero start and most British Leyland's had cast iron engines. LOL

Mike

Couch Potato

Mike,

With all this bad karma you keep spouting re Wren, you're due for the mother of all wet starts with your kero start turbines.

Wren Turbines USA

My Feedback: (39)

We actually did build a Wren 160 with all 4 mm piping....absolutely no difference in performance. So is there really a need to change the 100. If 4mm is better for your application, use it up to the motor...then use a 4mm to 3mm reducer Festo to connect.

As for Bald Eagle....I have come to expect his expert knowledge and free input on all things pertaining to our motors. Kinda funny sometimes, but more time than not ....just sadness!!
Gee Mike, maybe you should start your own turbine manufacturing company...you make it sound so easy!!

PaulD

My Feedback: (39)

I'm sure 95% of the fuel pressure comes from the pressure drop thru the needles in the fuel rail. It's needed to get good atomization of the fuel and might have something to do with the lower fuel consumption. 3 or 4mm line in a turbine this size will make no difference at all.

PaulD

Xairflyer

My Feedback: (1)

If it makes no difference why not make the fittings 4mm as other turbines saves having to use additional fittings - more chance of leaks/problems

joeflyer

My Feedback: (48)

That's the way it should be, however if the lines are too small then there will be a greater pressure drop in getting fuel to the needles.

I was responding to Goose's comment regarding the pressure the pump runs at and the amount of power required. The difference is that if the pump has to work harder to deliver the fuel through 3 mm. lines then it will consume more power and affect the reliability and longevity of the fuel pump.

I have confidence in Wren and their engineering capability. At some fuel flow rate it makes more sense to upsize the lines. My guess is that they are getting close to that point with a 22# engine.

Joe

BaldEagel

If it happens I will take it on the chin and report it on here and if I can the reson why.

Mike

BaldEagel

Perhaps I will at least it will have Kero start from the begining and not full of empty promise's about when it will be available.

Back in October 2007 I contacted Sarah Parish about the availability of the Kero start on Wren turbines I was told that Wren had it working and it just needed a software update, I wanted to buy British, but I wanted Kero start, I am still waiting, and you are supprised I am a little bit peeved.

Mike

craigdyer

BooHoo Bald Eagle,Grow up and build a bridge, If you ain't got nuthin nice to say dont say anything at all.

ww2birds

My Feedback: (14)

Just did the first flight on my Wren 100, replaced the SuperSport on my BTE Reaction 54. Report over on that thread .. but the one word summary is: "SUPERB!"

:-)

Dave


See: [link=http://www.rcuniverse.com/forum/fb.asp?m=10089038]http://www.rcuniverse.com/forum/fb.asp?m=10089038[/link]

mk1spitfire

+1

gooseF22

Joe, the inlet fuel line has no significant bearing on the fuel pressure due to the nipples/inlet barbs...etc..... As Ron Said... the voltage induced pressure is driven primarily from the nozzle tip diameter and case pressure. the holes are so tiny, as is the inlet inside the motor. the 3mm can provide more than enough fuel. the voltage keeps increasing(thus the current) in the pump until the motor achieves WOT 160K rpm, so the nozzle tips diameter becomes the governing parameter on how , but the better it atomizes, the more efficiently it achieves that rpm..

The motors I have seen run on the test stand at Rons at WOT, most all of them have a good high fuel pressure. That gives good atomization. Everything in a turbine is a balance. You want a good high fuel pressure but it cannot zap the battery. When I ran the SS/fltworks last time at 48PSI fuel pump, it was pulling 4 amps from the battery.. . The flightworks 200 pump is up to the task in the 100, as is the 400 in the 160. I was pretty darned impressed at this new setup.

When we ran volt/current tests last year at this time, the smaller motors pulled around 10 amps on start (propane start), less than 1/2 amp at idle and 4 amps at WOT. the Wren 160 was roughly double that, and both made 48+ psi pump pressure. During development of 160, Mike told us he opened up the nozzle just a tiny bit to achieve that balance of pressure and power consumption. I was very impressed at the work that was put into the development BEFORE it ever hit the streets...

The motors start nicely, run very well, are very reliable, and keep running.. the 100 is going to be an excellent "small block" motor for anyone that wants to keep it light with 20+lb thrust.. thats alot of planes!!

BaldEagel

Forums are for the free exchange of ideas and information good or bad.

Mike

Eddie P

My Feedback: (4)

Thanks for the great flight report!

JohnMac

Well here is some free information and rather good in my opinion. My normally superb Supersport started to stick on the first start up of the day. Not a huge problem as once it was free (application of a finger) it ran as normal. Nonetheless I dropped it back for them to take a look at. They told me that the engine was serial No.1 and had an ali shaft tunnel. Later engines had a SS shaft tunnel. It also had rear preload. So they have brought it up to the latest standard for me and now it is outputting out 8.4 kgs of thrust, certainly more than before.
And the cost? Zilch! Nix! Not a penny!
Once again I have to say: Thank you Wren!