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Air filters
#1
If you look on page 7 of my build log, you will see a beautiful Angel CH7 helicopter, which I re certified last week.

The owner reported that on a recent calm HUMID day, he could barely get enough power to get airborne. He thought that the reason was the humidity.

I thought that he should hover it WITHOUT the airfilter. And up she went! Airfilter looked good, but was dirty enough to cause a significant performance loss.

Having no MP gauge, the pilot has no real idea of how much power he has, other than his knee, I suppose.

I have a wonderful left knee. But I'm still going to have a Manifold Pressure gauge!
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#2
A manifold pressure gauge on a 2-stoke? how you going to do that?
Why not just keep your filters clean?
Skeeter
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#3
Why? Because you do not know if you can hover up that big tree!
Oops oops, nearly there, nearly there, why are my revs spooling down....
Maybe I should not have done this.
Can I back down - and back past that branch --
Overpitching~~~~
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#4
OK, I know about MP and performance charts, I own a Cessna with CS prop. My question is, how are you going to set this up on a 2 stroke? The crankcase is separated between each cylinder, are you going to run 2 MP gauges? The reed valves would play havoc with such a gauge, I would think. I guess I just don't see this as big an issue as you. If however you can make it work, I would be interested in your data.
Skeeter
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#5
There was an article recently in, I belive it was Kitplane magizine where dual water filled tubes were used to measure the vacuum to each cylinder. The tubes were connected to the primer ports on each carburator. This has several benifits. You can measure the balance between the two cylinders to see if you have your jetting and throttle cables are set correctly. I also think that there is a benefit to knowing the power being used. I have talked to Dwight and he uses a elctronic device to do the balancing and says that it helps both power and smoothness. I think he did this on Eddie's machine so maybe he can comment on this. I am using the Enigma EFIS on my mosquito and have already purchase the thermocouple unit with the MAP sensor in it. I have also purchased an additional sensor that matches the unit used in the thermocouple unit which I plan on connecting to an analog input. Going back to the artilce, I belive the reason that the water filled tubes work is because of the damping effect of the water. My plan is to machine two small air chambers with a threaded insert for installing different size jets to see if I can duplicate the damping of the water. I will post pictures as I get more into this project.
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#6
Good luck with that, I guess it just seams like a lot of work for a minimal gain. Now, if you have figured our how to shield all the RF from the MZ engine, that I would be interested in. Flew about 30 minutes today, I'm starting to hear all kinds of strange noises.......... :o
Helicopters, what a different animal! Smile
Skeeter
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#7
Hey Skeeter,
How much total time do you have on your ship? I think as we get more and more time on our Mosquito's we tend to become more aware of sounds that were probably always there but now we are more comfortable with the machine and start to notice these sounds. The RF problem has always been there and I'm not sure you will ever get rid of it totally. Eddy seems to have the least amount of trouble with RF. Although he will still have small issues with it from time to time.

The MP gauge ( manifold pressure gauge ) has to my knowledge never been used on a Mosquito Helicopter. I've used them in most of the certified helicopters that I've flown but in all of my flying of the Mosquito I just don't seem to need it. Rob seems to have quite a bit of helicopter maintenance experience and he may be able to figure it out. If he is successful then we all sorta win and if it can't be made to work then we will be able to put this issue to bed once and for all.

This next subject is for anyone interested.
I think I might have mentioned this before but guy's be very carefull and try not to make your instrument panels look like the panel in a 747. The Mosquito's are a very simple and safe helicopter to fly. The instruments that come with you kit is all you really need to safely fly and have fun with. I'm sure by now all of you have all watched some of John Sniders videos and have watched his instrument panel in action. His is very simple and basic and I doubt any of you will ever ask your helicopter to do more than what he shows us his helicopter can do. I'm sure John from time to time will glance at the instruments panel ( as all good pilots do ) But you also have to wear this helicopter, you've got to fly it by it's sound, by it's feel and by your gut. You have got to get your head out of the cockpit and look around. The more systems you install the more things that can go wrong.

Hey Everyone have fun, fly your ships, don't make everything so complicated and stressful.
I sure hope to see all of you at the Factory Fly-in. The Harley-Copter will be there and you will get to see a really simple helicopter in action
Thanks
Andy

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#8
Thanks for your input guys. I can see that I could have a hard time making this MP gauge idea work.
It's also plain that there is no great problem in the first place; we naturally adapt to sound feel and instinct with a machine once we know it well, as Andy points out.
But it will be an interesting exercise anyway, so I guess I'll persevere and we'll see what happens.
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#9
10-4 on the noises always being there. I'm just paying more attention I guess. I have 4 hours in the XE3, most of it just practicing around the ramp, quick stops and such. I did fly it around the pattern Saturday a few times, and notice the different sounds the blades make during each phase of flight. I agree the panel should be kept minimal, and Dwight has helped us with that by providing very little area to put anything Wink
I did install a com and X-ponder, a small altimeter, and a loading dock for a GPS. Each time I fly, I do a thorough post flight, and have found nothing loose, or broken. This is a real confidence booster. Looking forward to next weekend, so I can fly!
Skeeter
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