Edhamp

Here are some pics of the birch ply engine baffles. They do not look too bad once in place with the engine. Lets hope they help.

Edhamp

To update on progress if anyone is still following this, last weekend's continued testing was postponed because I was still not happy with the engine performance from previous flights. Good job I did because I have now found out that EVO160s apparently run better and are easier to tune if the throttle opening is limited to around 5/8-3/4 of maximum. To this end the engines are fitted with a throttle limiter stop plate to prevent the throttle from opening fully. This is because, so I am told, testing with the fitted Walbro carb showed that there is no increase in power after 3/4 throttle, just a decrease in fuel draw, I,e mixture weakens so revs drop. With the throttle limit in place the issues with fuel draw are negated without loss of any power.

Well for whatever reason, my engine does not have this limiter plate being an early example so at full throttle and under load in the air the mixture was beginning to go weak and the power drop off due to lack of fuel draw. Bringing the throttle back would restore power as the fuel delivery situation improved to produce the right mixture with the revs increasing, my symptoms exactly. I was able to produce this effect on the ground with the cowl off, getting an increase in RPM as the throttle was closed. No amount of high needle adjustment would produce the max possible rpm with 100% throttle opening. Max rpm would occur only with the throttle slightly closed. In the air under load with increased fuel demand and possible running hotter, the effect it is likely to be exaggerated.

It is a disappointment that I have to put an expensive model at risk, not to mention a lot of time and effort and cost to get to the bottom of this. It begs the question why this oversized carb was used in the first place if the fuel metering does not match the engine needs. No doubt there will be a technical or other reason for this.
So would a fuel pump help?. Well I will leave that to someone else to try, I will go with the technical fix which is a simple mechanical limit (as limiting the throttle opening with just your radio is too risky in my view).

Well it is a shame, I had hoped this engine would buck the trend with radials and work out of the box so I could avoid the inevitable testing and development phase that customers of some other new products have to go through before they can just enjoy flying. I shall retune at the limited throttle setting and hope that I still have sufficient power as I am advised I will. There are not many sub 50lb cowled warbirds that this engine will fit so it needs all the horses it can produce. Before this I would have happily given this engine 8/10 for ease of starting, excellent idle mid range quality etc, Now I am not so sure, maybe 6/10 at best. but I may reappraise my criteria for buying it relative to what else is out there for my next radial model.

stivvy

Hi Ed,

Hope you have the engine issues sorted. I will be adding the baffles to the cowl to keep the Moki cool(er).

Just wondered if you had flown the bird again ?

By the way, where do you do the test flying with the LMA ?

Steve D

Edhamp

Hi Steve,

Thanks for the enquiry. Not re-flown as yet, it is out of my control as I have to fit in with the LMA inspector's availability. Not sure how far you are in the process but the procedure I experienced is that they will allocate an inspector once you register your model, it will then need to pass a ground inspection prior to any flying so that you can apply for a "permit to fly" certificate from the UK CAA. The flight tests then include a full hour of logged flying and these can be conducted at any suitable model approved flying site. I started the process last year. The good news it does not cost you anything( apart from your LMA membership) plus off course you get some invaluable help and advice.

Ed

stivvy

Cheers Ed,

Yes I'm registered.

Does an inspector visit you mid-build, or is this unnecessary as it is ARTF ?

Steve

Edhamp

My inspector was happy to see the model on completion, given it is a proven ARTF, it is just a case of checking for correct servos, linkages etc etc as any normal large model builder would use who knew their stuff. In the end he was not happy with the fact that you could twist the tail plane and flex the rear fuse in the area below the rudder despite the formers for the tailwheel in this area. I had to add some strengthening in the form of some carbon cloth tape glassed in this area (more weight!) to makes things a bit more rigid but I could see it was a good idea.

stivvy

Thanks Ed - forewarned etc.
I will check mine.

Steve

ram3500-RCU

My Feedback: (221)

WOW! Your airworthiness process is very comprehensive. Sounds like it is all about safety though, being free of fees. A similar program in this country would most certainly not be. I would almost accept such a program, for the permission to build larger. We do have a waiver program, but hardly the size latitude you folks have.

Anyway, thanks for posting your experiences with the 160. It has been an engine I have wondered about, looking for more radial options.

Edhamp

You guys across the pond do not know how lucky you are when it comes to this hobby
-less red tape
-some of the best purpose built flying sites and club facilities in the world - you will rarely find model tables, stands, covers etc here. Unless you are lucky enough to fly from an active airfield, most will have a muddy field with no facilities, usually in the middle of nowhere shared with the local farm life (no doubt someone will pop up and say what a wonderful site they have but believe me it would be the exception to prove the rule).
-much cheaper RC gear all round, expect to pay 30-50% more for the same stuff in the UK.
-cheaper fuel
- great meets and shows (some of ours are OK but all a bit similar)
- competitions not stuck in the past like ours both in terms of the typical models entered and the way they are operated.
- and for the most part some great flying weather if you live in the right places!
end of rant[:@]

The odds are against us large warbird builders here. I recently asked the question as to how many CARF Corsairs had been certified in the UK (assuming that most people will struggle to get under the 20kg limit using any king of radial engine so virtually all those sold in the UK if built would legally need testing before flight). So far I can account for 3, plus mine, with a couple I know off undergoing construction. Not exactly a lot for the whole of the UK. If you have a CARF corsair and are flying it in the UK then please let us know your experiences and join the club. I am throwing open this thread.



cheers
Ed

ram3500-RCU

My Feedback: (221)

So you say that the grass is not always greener on the other side of the ......... pond. I now have greater appreciation for my fellow modelers overseas. Do you have much youth involvement given what you describe? I hope so.

Edhamp

CARF F4u4 kit bash EPILOGUE

I know you guys like to see the proof so some vids of the dash 4 version. Certification flight tests all completed and I am enjoying flying it this summer. I think I have now managed to get the best from the Evolution 160 Engine and as I get used to the model I am more and more happy with the combination. Take-offs are effortless, have the power to loop and roll without having to build up energy first, the model climbs easily. Remember this is a 50lb model so not too heavy for an approx. 10hp engine.

http://youtu.be/dDdgcZfcT48

Model is fast when needed and the sound of the engine on the standard prop is also pretty good, somewhere between a Moki 150 and 250.

Landings are straightforward, easier than my CARF Mustang, as long as you do not come in too slowly and make sure you land on the mains, no three pointers. Virtually no rudder needed on take-off even in a moderate cross wind. People keep asking if I have a gyro fitted! A gyro might help in the air as can sometimes waggle the tail.

The negative side- some poor technical aspects for the engine, namely a useless choking system, first starts after a lay up require access to the primer bulb, the only model gas engine I know that has one (the Walbro carb used must have been borrowed from a grass strimmer or something!) This is not easy in a cowled model as the carb is buried behind the engine . Once properly primed starts easy. Carb needs a factory fitted throttle stop, simply looses power otherwise as engine cannot operate with throttle butterfly fully open, Do not believe me? Check the after market throttle stop plate being sold by Horizon. It still annoys me as this just does not seem right but the engine seems to be delivering the power.

On the plus side you do not need a fuel pump if running the factory carb set-up which keeps things simple.

Prop shaft is too short for wooden props (maybe this has been rectified on later versions of the engine, which I also think come with a six bolt prop fixing. I would not use a wooden prop on this engine, the last one I tried (a quality 3W prop) shattered! Composite is the way to go if you do not want a loose prop.

Forget a nice scale looking prop or three blade. For me engine works best with 28x12 2 blade, giving around 5000rpm . The 26x12 3 blade I tried initially just did not do the job in the air with this engine.


cheers
Ed




.

Edhamp

Second short vid is now here.

http://youtu.be/JQ6W-vFN0Kg

You do not get a wide throttle range with this engine but that is about 2/3rds throttle.

JohnMac

Wow, that looks great Ed. I cannot wait to see itfor real. I will try to be there on the 17th.
John

Edhamp

Thanks John. This is fast becoming my favourite model to fly. The overall ocean blue colour scheme is a bit lost against our cloudy skies. The last Corsairs in Marines service had a nice scheme but CARFS version would need a lot more work to get the shape right. Ive seen stock CARF Corsairs painted in this scheme and they just do not like right . The dash 5 looks like a dash 4 on steroids!

Cheers
Ed