Skeeter Jr.

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.
Apples&Oranges yes, but for what it's worth, these two engine driven fans, about 9" dia., running at about 10,000 RPM, kept my 180HP Lycoming cool, hovering for an hour on a 100degF day at 1670# takeoff weight and 95% wide-open throttle.
 

Attachments

  • HELIFAN9.JPG
    HELIFAN9.JPG
    23.5 KB · Views: 11
  • HELIFAN8.JPG
    HELIFAN8.JPG
    22.4 KB · Views: 11
  • HELIFAN7.JPG
    HELIFAN7.JPG
    25 KB · Views: 10
Sounds good to me but should we be comparing the rotor shaft torque rather than the engine torque. Obviously an engine running at a higher rpm will have a larger reduction gearbox to obtain the correct tip speed and therefore will produce more torque at the rotor shaft?
Absolutely right mate, Rotax quote there torque at the crankshaft not the prop shaft so the gearbox reduction is the first stage of reduction before driving the rotor.
But if the Yamaha is spinning at 6100rpm the total amount of reduction for the same rotor rpm will be pretty similar to the rotax at 5500 crankshaft rpm.
It will be interesting to see the outcome.

wolfy
 
I had interest in the 120 vector motor for a while but did not want to go through all the testing and find out it would not work.
until John H installed one in a Mini 500 it was touted as working so well that I thought I would try one in the Helicycle. Extensive dyno testing showed that the engine only produced 100 to 105 uncorrected HP. engine manufacturers add in correction factors to there HP ratings for a "Standard Day" meaning perfect testing conditions. My testing criteria was 100 continuous HP@6500RPM for 1 hour.
The engine never made it after 45 minutes the breather on the oil tank looked like a volcano. Just a solid column of blow by.
I replace the rings and decided to give it a try in the Helicycle anyways. as I suspected the engine was underpowered. on a cool day it performed marginal on a hot july day the only way to get it off the ground was 6800 RPMs and underpowered. I did about 3 hrs of hover testing and I had my volcano breather back .My empty weight was 575 my take off weight was around 800 I am sure the reason it worked better in the mini was they were a little lighter than I was. After more research I found out that even in the mini 500 they were also underpowered. and after a claimed 40 HRS one had burned valves. I could never pin them down to a specific RPM they were operating at but it was far more than what they were advertising. it is a good motor and should work well in a helicopter with a gross weight at least 100 lbs less than what I was. I did turbo the motor also got more HP and less durability that engine never went into the helicopter.

Doug
 
Apples&Oranges yes, but for what it's worth, these two engine driven fans, about 9" dia., running at about 10,000 RPM, kept my 180HP Lycoming cool, hovering for an hour on a 100degF day at 1670# takeoff weight and 95% wide-open throttle.
Mr Brian, good to se you surface again. I trust all is well with you and your dearest.

Am I correct to assume you had these fans on your Brantley?

Cheers, F.
 
So that is at least two helicycles that have tried one then.

wolfy
Guy's, as I said before, it is well known that the Genesis 120 is a lot lesser of a grunt engine than the Genesis 130FI. So far I am the only one going to try out the 130FI, Luciano was another fellow, but he has unfortunately passed on. His project still remains untouched and stored in the UK. The lower cc'd carby 120 is all that we have known experience with. I will admit, I'm putting my hopes on the fact that my engine has FI and an ECU. It senses and corrects, so it has the potential to remain longer at "standard day" output during varying conditions. Then, I'm lighter than the test subjects, and don't have to swing my rotors to 620RPM. Not too long now, we shall know the answer.
 
Guy's, as I said before, it is well known that the Genesis 120 is a lot lesser of a grunt engine than the Genesis 130FI. So far I am the only one going to try out the 130FI, Luciano was another fellow, but he has unfortunately passed on. His project still remains untouched and stored in the UK. The lower cc'd carby 120 is all that we have known experience with. I will admit, I'm putting my hopes on the fact that my engine has FI and an ECU. It senses and corrects, so it has the potential to remain longer at "standard day" output during varying conditions. Then, I'm lighter than the test subjects, and don't have to swing my rotors to 620RPM. Not too long now, we shall know the answer.
Sounds good mate I'm sure it will be ok, hopefully it performs to your expectations.

wolfy
 
Mr Brian, good to se you surface again. I trust all is well with you and your dearest.

Am I correct to assume you had these fans on your Brantley?

Cheers, F.
Yes. These were the factory-installed fans on all B-2b's. B-2's and B-2a's had a different setup for cooling and it
never worked real well.
 
Yes. These were the factory-installed fans on all B-2b's. B-2's and B-2a's had a different setup for cooling and it
never worked real well.
Thanks for the ask. The fam is all good. And yours?
 
Hi Francois.

I was wondering about the clutch you have used, is it the standard m500 clutch? If so can you tell me anything about it? I have used an RK400 friction pad set on my contraption and I don't know yet if it will work. Any information you have would be appreciated

Thanks Ben
 
Hi Francois.

I was wondering about the clutch you have used, is it the standard m500 clutch? If so can you tell me anything about it? I have used an RK400 friction pad set on my contraption and I don't know yet if it will work. Any information you have would be appreciated

Thanks Ben

If it is a Mini-500 clutch, I used a kevlar pad. I bought the pad in sheet form, cut them to size, then used the same bonding film I used on the tail rotors to bond them to the weights. I had to make a spring-loaded fixture to put constant pressure on the pad while it was in the oven at 250F for 2 hours. After, we machined the edges of the pad to smooth the sides of the weights, and balanced each weight. We also used a composite pad on the sides of the weights to absorb the torsional vibrations. It was an involved process to make them work.
 
If it is a Mini-500 clutch, I used a kevlar pad. I bought the pad in sheet form, cut them to size, then used the same bonding film I used on the tail rotors to bond them to the weights. I had to make a spring-loaded fixture to put constant pressure on the pad while it was in the oven at 250F for 2 hours. After, we machined the edges of the pad to smooth the sides of the weights, and balanced each weight. We also used a composite pad on the sides of the weights to absorb the torsional vibrations. It was an involved process to make them work.
Wow, thanks for that Dennis. I wondered if it was your own clutch that you had developed. Did you test the maximum torque it could drive? Can you tell me anything about the RK400 in comparison?
 
Wow, thanks for that Dennis. I wondered if it was your own clutch that you had developed. Did you test the maximum torque it could drive? Can you tell me anything about the RK400 in comparison?

The first prototype Mini-500 used a multiple-matched v-belt system engaging the idler drum with an emergency brake handle from JC Witney. I soon after used an electric motor with micro switches to keep the adjustment. Next, I wanted to stop wasting power with v-belts and use a toothed belt, which meant I needed a clutch.

I first used the RK400 (which is meant to be an electric motor clutch). I bought one with a smaller mounting hole so I could machine the Rotax taper on the opposite side, to keep the weight retaining place accessible if need be. That clutch only worked a few hours until the friction pads were coming loose and disintegrating. Then the clutch fatigue cracked and broke off at the end of the Rotax taper where the weights were bagging the walls of the housing. Old Brian was flying. It broke on takeoff climb out at about 150 feet and Brian autorotated in a 90-degree turn and landed it on an upward slope on the golf course. Nay a scratch!

I then redesigned the clutch body with a new type of steel, added radius in all the corners for stress relief, heat-treated it, and changed the weights, and added the new friction pads and absorption pads. I also had new springs made so the engagement RPM was a little higher. We ended up manufacturing everything, buying nothing from the original RK400 clutch. However, the basis of my design was from the outright theft of the RK400. Good engineers borrow good ideas. Great engineers outright steal them.
 
Hi Francois.

I was wondering about the clutch you have used, is it the standard m500 clutch? If so can you tell me anything about it? I have used an RK400 friction pad set on my contraption and I don't know yet if it will work. Any information you have would be appreciated

Thanks Ben
Hi Ben,

Just as Dennis has replied, it's a stock M-500 clutch, a much improved RK400 knock-off. But what a friggen struggle to get those shoe retaining springs on...

It's easy to pop the clutch assembly off the motor shaft with the special tool, but I need to find a way to pull the clutch assembly apart, without having to remove the outer plate and pull out the 4 shoes to expose the 4 threaded holes to pop off the clutch shoe housing from the inner spindle, in order to get to the 4 low profile hex bolts that hold on the drive sprocket. Those 4 little countersunk hex bolts that hold in the outer plate just scream "strip me". Once they are punched in place and you change your mind, you struggle to remove them. Dennis, do you remember off by heart what the thread size of those 4 little countersunk hex bolts are? I need to prepare to remove the outer plate to get to the 4 threaded holes to pop off the shoe housing assembly.

Cheers, F.
 
If it is a Mini-500 clutch, I used a kevlar pad. I bought the pad in sheet form, cut them to size, then used the same bonding film I used on the tail rotors to bond them to the weights. I had to make a spring-loaded fixture to put constant pressure on the pad while it was in the oven at 250F for 2 hours. After, we machined the edges of the pad to smooth the sides of the weights, and balanced each weight. We also used a composite pad on the sides of the weights to absorb the torsional vibrations. It was an involved process to make them work.
I think I determined through my engineer contact at 3M that the adhesive you used was ScotchWeld AF-126 green Aerospace structural adhesive film 0.06 weight. It works much better if you preclean with an alkaline degreaser and prime with 3M Ew-5000 bond primer.
 
Hi Ben,

Just as Dennis has replied, it's a stock M-500 clutch, a much improved RK400 knock-off. But what a friggen struggle to get those shoe retaining springs on...

It's easy to pop the clutch assembly off the motor shaft with the special tool, but I need to find a way to pull the clutch assembly apart, without having to remove the outer plate and pull out the 4 shoes to expose the 4 threaded holes to pop off the clutch shoe housing from the inner spindle, in order to get to the 4 low profile hex bolts that hold on the drive sprocket. Those 4 little countersunk hex bolts that hold in the outer plate just scream "strip me". Once they are punched in place and you change your mind, you struggle to remove them. Dennis, do you remember off by heart what the thread size of those 4 little countersunk hex bolts are? I need to prepare to remove the outer plate to get to the 4 threaded holes to pop off the shoe housing assembly.

Cheers, F.
Just sent you a dwg to fr...@bigp....
 
Some stuff.
 

Attachments

  • shoe weights start.jpg
    shoe weights start.jpg
    18.5 KB · Views: 10
  • dialing in nunbers.jpg
    dialing in nunbers.jpg
    114 KB · Views: 10
  • dialing in shaft.jpg
    dialing in shaft.jpg
    133.5 KB · Views: 13
  • dialing in clutch.jpg
    dialing in clutch.jpg
    147.7 KB · Views: 12
  • WEIGHT MATCHING SHOES.JPG
    WEIGHT MATCHING SHOES.JPG
    10.4 KB · Views: 13
Thanks Brian, I'll check once I get home tonight.

I'm still hounding you for the pitch arm combo drawing.....

Cheers, F.
I did look and I have a 90% finished model of the cast arm, and a finished model of the plate it bolts to. I do not have a 1-piece like Hawkinberry made.
 
Top