Skeeter Jr.

HobbyCAD

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After importing the Yamaha Genesis FX Nytro 135HP EFI engine from the US in 2010, having it stored away, dragged out for fitting, packed away again, and so it has gone on for 10 years, at last the end is in sight. I have developed a custom engine electrical harness so that the ECU processes only the basic engine functions. It was a great leap of faith. Well, tonight, without any hassles, I powered her up for the first time, went through the checks, and hit the start button. It purrs like a kitten. What a great leap of progress!!

 

Eric S

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Some last items done before I'm able to start her for the first time.
What brand is your muffler and flex exhaust hose and where could I buy it? It looks like the perfect solution for a Subaru project I'm working on.

Thanks,
Eric
 

DennisFetters

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Is that electric fan all you have for the cooling? I found out the hard way, they lie about the CFM. I spent 6 months trying to make the electric fan cooling on the Mini-500 work, and it would overheat in 5 minutes. Solved the issue with the belt-driven fan.
 

HobbyCAD

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What brand is your muffler and flex exhaust hose and where could I buy it? It looks like the perfect solution for a Subaru project I'm working on.

Thanks,
Eric
Eric, I sources the flex tube years ago, let me see if I ca trace it's origin. As far as the muffler goes, I found it at a local recycle centre. It fitted my requirements, symmetrical shape, centralised inlets and outlets, adaptable inlet mounting. It has a Husqvarna logo stamped onto it.

Cheers, F.
 

HobbyCAD

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Is that electric fan all you have for the cooling? I found out the hard way, they lie about the CFM. I spent 6 months trying to make the electric fan cooling on the Mini-500 work, and it would overheat in 5 minutes. Solved the issue with the belt-driven fan.
Hi Dennis, good to hear from you again. From your avatar, you back in Abu Dhabi? I still hold fond memories of my 10 years over there.

You are correct, cooling efficiency can be a black art. I stuck as close as possible to the original Yamaha sled's cooling configuration. I'm using the exact thermostat unit, it was a stand-alone mount in the sled, I mounted it as the same stand-alone. My hoses are the same diameter and routing configuration, and I'm using the same coolant temp sensor that talks to the ECU, and using the ECU's fan rely output to trigger this radiator fan. So all and all it should have a good chance at success. I am still to install a stand-alone Swift dual gauge instrument to monitor the oil press and coolant temp. This should, when it eventually gets running with rotors turning, give me an indication of the temp or temp fluctuations of the coolant coming out of the engine. Another thing going my way is that the entire contraption is out in the open, nothing is enclosed.

Cheers, Francois
 

DennisFetters

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Hi Dennis, good to hear from you again. From your avatar, you back in Abu Dhabi? I still hold fond memories of my 10 years over there.

You are correct, cooling efficiency can be a black art. I stuck as close as possible to the original Yamaha sled's cooling configuration. I'm using the exact thermostat unit, it was a stand-alone mount in the sled, I mounted it as the same stand-alone. My hoses are the same diameter and routing configuration, and I'm using the same coolant temp sensor that talks to the ECU, and using the ECU's fan rely output to trigger this radiator fan. So all and all it should have a good chance at success. I am still to install a stand-alone Swift dual gauge instrument to monitor the oil press and coolant temp. This should, when it eventually gets running with rotors turning, give me an indication of the temp or temp fluctuations of the coolant coming out of the engine. Another thing going my way is that the entire contraption is out in the open, nothing is enclosed.

Cheers, Francois

Hi Francois,
Yes, back in UAE, this time in Abu Dhabi working for a government-owned company building a new UAV helicopter. Progress got delayed over a month while I was recovering from COVID 19, but I'm back in the office for the last week.

I hope the cooling system works out for you. The only way I could get electric fans to work was on the SVU-200 UAV helicopter by having two BAF's (Big-Ass Fans), one to pull the air in and force it up through the radiator, and another on the other side to pull it through the radiator, and I needed a shroud to use 100% of the radiator surface. It would never work here in the UAE, but it worked well on normal days in China. I first used two 24V electric fans to pull through the radiator in the Mini-500, both even ran off a separate dedicated generator, and with both side panels off and I still could not run 5 minutes at hover power without overheating, and that was with a Rotax 582.


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HobbyCAD

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Hi Francois,
Yes, back in UAE, this time in Abu Dhabi working for a government-owned company building a new UAV helicopter.

Hi Dennis,

How many UAV heli or VTOL programs do they want over there? In my days, it started with the Schiebel Camcopter, which was followed by a local version. Are you part of the Garmousha gang?

Cheers, F.
 

btd1982

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Just Found this thread. Beautiful work Francois.
 

btd1982

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It takes some dedication to build something like this particularly if you're doing all the work yourself. Years of work evenings/weekends but what an achievement it will be!
 

HobbyCAD

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It takes some dedication to build something like this particularly if you're doing all the work yourself. Years of work evenings/weekends but what an achievement it will be!
This project has been haunting me since 1990 when I first saw the Skylark, a copy of the Cicare CH-4, during a visit to Joel Levin's in Fallston, MD. I left there with an original set of the CH-4 plans under my arm. I then started getting together a treasure of info as source data to what was going to become my project. From scouring the library in the basement of the Smithsonian where I found the plans of the Hoppi-Copter, to Anaheim where I found a full set of the Weilage Boon Jr plans. I found a full set of the early Helicom Commuter plans, and a ton of other drawings. Of course, the Adams Wilson AW-1 is amongst them, and all the Scorpion I, II, RW-133, RW-145 build drawings. I got all 3 of Prouty's books, plus his big fat red textbook and started figuring it all out. I then found a copy of Pop Emich's design procedures in amongst the Helicom plans, and this was my big break. I could now follow the bouncing ball from the first parameter to a full set of design numbers. Whilst in Chile in 1993, I discovered Agusto Cicare's CH-5 across the border in Argentina. I there and then made the decision that this was what I wanted to end up with. Not a CH-7 Angel, not a Mini-500, but an open framed CH-5. I contacted Agusto Cicare, but after his disputes with Dennis and his M-500, and the Barbero brothers with their CH-7 Angel, he was not willing to pass on any drawings or design, not at any price. He did send me some pictures though. I then decided to have to go it alone, and set out to work on what was the foundation of my today's Skeeter Jr. In 2010, I settled down from my worldwide adventures, enough to plant a peg in the sand, and start the physical project. This is when Skeeter Jr was born. Today we are 11 years, 2 jobs and two kids down the line, and she is close, oh so close to the point where the rotors will be driven. Along this build journey, I give credit to Dennis Fetters, Chuck Beaty, Barny Bahle, John Higgenbotham, Brian Cobb, Don Hillberg, and many others I may not recall right now, all have played a part in helping me achieve my goals. I've just about done it all, all parts fit to their mating parts, sections have been put together, I just have not finally rigged it all. The last major task is the final setting up of the MRT internals, this starts next week. The internal oil pump it the biggest hurdle, it's implemented, but I need to run it on the ground to flight RPM in order to ensure it does not pump too much volume, at too high a pressure, causing the oil seals to pop out from their seats. After that design confirmation, it's final assembly, static setup and balance, and then the big day of turning the rotors under power.

Cheers, F.
 
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DennisFetters

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Hi Dennis,

How many UAV heli or VTOL programs do they want over there? In my days, it started with the Schiebel Camcopter, which was followed by a local version. Are you part of the Garmousha gang?

Cheers, F.

They have always been looking for something with better performance than the Schiebel. Even ADASI has been trying over the past years after buying a French two-place called the Dynali and trying to convert it into a UAV, calling it the Garmousha, and failed to even fly it yet. The Chinese did the same thing with a Dynali and got it to fly.

The problem is always the same, they are balanced for people to be inside, so you always have to have ballast, which is extra weight, that reduces potential performance.

More than two years ago I was invited by Mubadala in Abu Dhabi to present my StarLite-2A design. When I got there ADISA was sitting across from me. I asked if they realize ADISA was my competition, and I was told they were invited to evaluate my design. I said that's like inviting the fox to look over the hin house. I went ahead and allowed them to see the design and answered their technical questions. I didn't know about their Garmousha project at the time. They did ask me my opinion about converting a manned helicopter to a UAV, and I told them it can be done, but more affordable and better results to make a helicopter for the job. I guess they found out I was right.

The company I'm with is not publicized, and they require it to stay that way.......


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2019-03-19-Dynali-0392 (1).jpg
 

btd1982

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This project has been haunting me since 1990, when I saw the Skylark, a copy of the Cicare CH-4 during a visit to Joel Levin's in Fallston, MD, and I left there with an original set of the CH-4 plans. I then started getting together a treasure of info as source data to what was going to become my project. From scouring the library in the basement of the Smithsonian where I found the plans of the Hoppi-Copter, to Anaheim where I found a full set of the Weilage Boon Jr plans. I found a full set of the early Helicom Commuter plans, and a ton of other drawings. Of course, the Adams Wilson AW-1 is amongst them, and all the Scorpion I, II, RW-133, RW-145 build drawings. I got all 3 of Prouty's books, plus his big fat red textbook and started figuring it all out. I then found a copy of Pop Emich's design procedures in amongst the Helicom plans, and this was my big break. I could now follow the bouncing ball from the first parameter to a full set of design numbers. Whilst in Chile in 1993, I discovered Agusto Cicare's CH-5, this was what I wanted to end up with. I set to work on what was the foundation of my today's Skeeter Jr. In 2010, I settled down from my worldwide adventures, enough to plant a peg in the sand, and start the physical project. This is when Skeeter Jr was born. Today we are 11 years, 2 jobs and two kids down the line, and she is close, oh so close to the point where the rotors will be driven. Along this build journey, I give credit to Dennis Fetters, Chuck Beaty, Barny Bahle, John Higgenbotham, Brian Cobb, Don Hillberg, and many others I may not recall right now, all have played a part in helping me achieve my goals. I've just about done it all, all parts fit to their mating parts, sections have been put together, I just have not finally rigged it all. The last major task is the final setting up of the MRT internals, this starts next week. The internal oil pump it the biggest hurdle, it's implemented, but I need to run it on the ground to flight RPM in order to ensure it does not pump too much volume, at too high a pressure, causing the oil seals to pop out from their seats. After that design confirmation, it's final assembly, static setup and balance, and then the big day of turning the rotors under power.

Cheers, F.
Sounds like you have done your research!

With regard to the electric fan how hard would it be to convert to a belt driven? I guess it would depend on the sustained demand for power in your skeeter when compared to the sustained demand for power in the sled for which the cooling system was designed. If they are similar perhaps the electric fan will be sufficient.

what empty weight are you on track to achieve ?

I decided to opt for a belt driven fan based solely on what others had done.
 

HobbyCAD

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Sounds like you have done your research!

With regard to the electric fan how hard would it be to convert to a belt driven? I guess it would depend on the sustained demand for power in your skeeter when compared to the sustained demand for power in the sled for which the cooling system was designed. If they are similar perhaps the electric fan will be sufficient.

what empty weight are you on track to achieve ?

I decided to opt for a belt driven fan based solely on what others had done.
I have the opportunity to, if the electric fan does not do the job, to implement a belt driven mechanical setup. I trust my oversized radiator sitting underslung and open to the airflow, with a temp controlled fan for the hover, will do the trick. We shall see how it pans out.

I'm hoping to get in under 350lbs empty. I have yet to weigh it, but soon I shall know. I'm a big guy, so I need to save every airframe pound in order to trade it for useful load.

Cheers, F.
 

btd1982

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350lbs empty weight and 135hp. It doesn't sound like the engine will be working that hard. Look forward to seeing the next stage. 👍
Ben
 

wolfy

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Do you think it will produce enough torque?
I think they were lacking when tried in the helicycle, but they are maybe a slightly larger chopper.

wolfy
 

HobbyCAD

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Do you think it will produce enough torque?
I think they were lacking when tried in the helicycle, but they are maybe a slightly larger chopper.

wolfy

Do you know if the attempt to repower the HeliCycle with a Yamaha Genesis engine used the 120 out of the RS Vector, or the 130FI out of the FX Nytro? When doing my selection, my research showed me that the 130FI has a lot more grunt than the 120, especially at the lower end. The peak sits around the 6000RPM range, so I geared my setup for this, 6134RPM. Max engine operating RPM for the FX Nytro is at the 9200RPM rev limiter, so I'm not working it that hard. The 120 torque peaks at 82lb/ft, where the 130FI peaks at 95lb/ft. The 130FI specs are 72lb/ft at 3500RPM, 95lb/ft at 6000RPM, and still at 94lb/ft at 7100RPM, so I should have a lot of torque available from just after clutch engagement, right up to past my max rotor RPM. The stock Rotax 582 torque peaked at 55lb/ft, but that was at 6000RPM. In the M-500, it had to run up to 6500RPM. I expect it thus flew with slightly less torque.

I should be good to go, I bloody well hope so, otherwise this 10-year exercise has been in vain, or I need to lose 25kg's to give it a better chance........
 
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wolfy

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Do you know if the attempt to repower the HeliCycle with a Yamaha Genesis engine used the 120 out of the RS Vector, or the 130FI out of the FX Nytro? When doing my selection, my research showed me that the 130FI has a lot more grunt than the 120, especially at the lower end. The peak sits around the 6000RPM range, so I geared my setup for this, 6134RPM. Max engine operating RPM for the FX Nytro is at the 9200RPM rev limiter, so I'm not working it that hard. The 120 torque peaks at 82lb/ft, where the 130FI peaks at 95lb/ft. The 130FI specs are 72lb/ft at 3500RPM, 95lb/ft at 6000RPM, and still at 94lb/ft at 7100RPM, so I should have a lot of torque available from just after clutch engagement, right up to past my max rotor RPM. The stock Rotax 582 torque peaked at 55lb/ft, but that was at 6000RPM. In the M-500, it had to run up to 6500RPM. I expect it thus flew with slightly less torque.

I should be good to go, I bloody well hope so, otherwise this 10-year exercise has been in vain, or I need to lose 25kg's to give it a better chance........
I think it was the 120hp 3 cylinder but not 100% sure. Doug S (spelling) who did the conversion used to visit here often but not sure about now days. Hopefully it is up to the task mate will be good to see it fly.

wolfy
 
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