CopperheadAV

Marc,

Thank you sir. Let us know how it goes and happy flights!!

Cheers,

Tim

AFSalmon

My Feedback: (3)

All, my name is Mike Pilkenton and I'm the main tech guy and designer at OMP. my email is [email protected] and please feel free to email me with any concerns, orders or otherwise, with the Venom engines. As Tim has stated he is taking care of business and quality control directly himself in China. Not too many companies put this much personal touch into their products. OMP and CHA have merged and we are undergoing some growing pains. Please be patient as we work out the bugs. Tim and I will work together to clean up the communication channels and hopefully nobody gets missed.

Thanks,

mfuess

To be safe, you could open up your topend "slightly", maybe 200 RPM down from peak. But I generally don't do this to my engines. If your tune changes in flight, you have a static air pressure problem around the carb.

The Big Kahuna

Thanks for the Tuning info Mark!
I have just finished a scratch build of a simplified Edge. With no cowl, do you anticipate that I will have any carby pressure problems?

CopperheadAV

Nice Hybrid!! Whos plane is that??

mfuess

It doesn't appear so, but you won't know for sure until you fly it.

Mitsu1

My Feedback: (13)

Hey, I have a question for any r all. Is it possible the carb pressure probs that some have discussed were this that I'm about to describe? I had a friend over today that has lots of experience with gas model engines and we ran my Venom 45 to tune it for best idle and transition. He got that Venom running so sweet and the idle so slow we were both amazed. One thing that he brought to my attention though, was the unusual number of turns out on the high speed needle where the engine made its best top end performance. It was almost 4 turns out, ... a point where it should have been running rich but was making a very smooth 7400 rpm on a Xoar 21 X 8. The engine was not lean or unusually hot, and the idle was a steady 1700rpm with this prop. The transition was smooth out of this idle as well. The only thing perplexing was this unusual number of turns out on the high speed needle. He noticed something and decided to do a little experiment. He said the choke butterfly on most carburetors is set to flow in the slipstream when open, but because of the way this carb was rotated, the butterfly is like a door hung out in the wind when it in the open run position. He surmised that this butterfly hanging out in the prop blast was causing turbulence at the carb opening, causing a starving for fuel, and requiring a more open high end needle to feed its need.

So with the engine runnng smoothly at 7400 wide open and the high end needle almost 4 turns open .... he simply put his hand between the carburetor and the prop blast ..... (Shielding the butterfly and the turbulence created from the prop blast smacking the butterfly door) ... and the engine immediately went to a 4 - stroking rich condition, which would be expected from a 4 turns out/open setting on the high end needle. As soon as his hand was removed, the engine would lean out and return to a smooth and consistent 7400. No cowl was on the plane as shown in the photo. We did this over and over and the results were always the same. We believe that if that choke butterfly had been turned to where it sliced through the prop blast as opposed to fighting the prop blast broadsided ... this condition would not exist. We are going to try a velocity stack, or better yet .. just the simple BB stack or whatever we can make .. to see if this helps. I don't see this as being a diaphram pressure problem since no cowl was on and the diaphrtam is on the rear side of the carb. ... Any thoughts?

mfuess

Your discovery is true on all carbs that have the same orientation.
A velocity stack will make a big difference similar to holding your hand between the carb & prop blast. So will installing your cowling to some degree. It may run super rich and your needles may have go in about 1 to 2 full turns. But, if it runs fine like it is why change it? 4 turns out isn't a problem on this carb. Mine are out that far and haven't had a single problem. Like you said, it idles great and the transition is great. So why creat a problem that dosen't exist unless you interrupt the tuned air flow? I was perplexed by this too, at first... but I decided to leave well enough alone and accepted the 4 turns out. I have 192 flights on my V45 and I haven't touched the needles yet.

7400 RPM is a little bit high. I like to keep them around 7000 to 7200. You may want to go to a 22x8.

The Big Kahuna

Tim, the hybrid is a super simplification of a D& L Designs Edge 540 27%. Iv e kept the foils and working surfaces as per Doug's design but simplifies the Fuzzz for quick build as a strong practice plane. I am a SPAD builder from way back so cheap, simple constructions that fly well suit my experimental nature. The 3mm Coreflute wings take about an hour to build but I have never broken one yet. Your Venom 45 rockets this beast around and any shortfalls are purely my flying skills.

72

How about some plans for us "design challenged" types????

Flyer Freq

It sounds like a neat project for newbies to gas![8D]

72

That's me- and I need something I can afford to play with and not break the bank.

3D_Junkie

Tim,
Any word on when the 30 will be out, and do you think it will hover an 11lb airplane? I have been looking for something gas in this size for a while.

The Big Kahuna

OK Guys, you can buy the Edge 540 plans from Douglas Lee for $31 incl. Postage USA at [link]http://www.dldesigns.net/edge.htm[/link] (Do specify the 3D version)Then, for cheap wing building techniques go to[link]http://www.spadtothebone.com/SPAD/[/link]. How you put the two together is as wild as your imagination. If you need help mail me.

CopperheadAV

I'm working on it right now. The prop shaft hub needed to be redesigned and I have been testing various designs for the past weeks. I have settled on a design and we are now life cycle testing. I should have the 30cc in the states by early next month. I will post a pic as soon as we clean up the parts.

Cheers,

Tim

CopperheadAV

I have been doing SPADS now for the past 5 years. Check the link Spadtothebone the big kahuna listed above. There are many designs available for free. My favorite is the PQHOR with an OS 32!!! I make these 3 at a time!!

Cheers,

Tim

72

I have been looking for something quick to throw together for my V45 and this looks good.
Tim, did you get my last email about the standoff's? Also, what glue are you using on these coro's?

CopperheadAV

No I didn’t, [:@] the typhoons are over for now and I have reasonable access again!! The Standoffs are in the states and my father has the hardware ordered, it should only be a few days. If I forget to email you, PM on the TPB in a few.

I have been gluing coro to coro and have been using some weird rubbery glue I got from the craft store, I forget the name. On a wing like that, the TBK will have to answer that one?

CopperheadAV

Sorry,

Yes 11lbs is fine.

The Big Kahuna

To glue coro ( corefluit plastic sheeting)
just lightly sand both sides and use any THIN contact adhesive. The coro will tear but the joint will not come unstuck.
Tim
What is the Max hovering weight for the VEWNOM 45?????

CopperheadAV

Hooks had a 17lb extra, not much punch from a hover so I wouldent excced that for 3D.

The Big Kahuna

There must be a rule of thumb for prom to weight ratio. More weight requires biger or smaller prop?

3D_Junkie

Thanks Tim, put me on the list for one when they come out. I have a 72" yak that is sucking the glow down like no tomorrow. I go through about 2 gal a month! I can't wait to get it running on gas. Save me some real $$$ in the long run.

Jason

mfuess

You should really be using a V45 for a 72" YAK.

3D_Junkie

The problem is this airframe is designed for a 140-160 size glow engine. The V45 is just too heavy. The YS120 pulls the plane with authority, but will only hover at full throttle. The YS120 spins a 16x6 at 9000RPM, while the V30 should be able to turn a 18x8 at 8000 RPM with only a slight overall weight increase (2-3 oz). The wing loading would be too high to be enjoyable with an extra 1.5 lb up front.