Electric Mosquito Prototype

MauiFlyGuy

MauiFlyGuy

Newbie
Joined
Oct 22, 2016
Messages
21
Location
Byers, CO
Aircraft
Mosquito 285 upgraded to 290 specs. (06/2021 @ Factory)
Total Flight Time
400+ (Total all types)
I was lucky enough to help Composite FX at Oshkosh 2022 when they reviewed their first Electric Prototype. First stats is that it will hover 20-25 minutes and 45 minutes in forward flight. Testing continues along with development of enhanced performance of their 285/290 variants. CFX is now producing their own rotor blades, which are now flying and are developing an engine that will replace the MZ 202 in the XEL and XE models.
 
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MauiFlyGuy said:
I was lucky enough to help Composite FX at Oshkosh 2022 when they reviewed their first Electric Prototype. First stats is that it will hover 20-25 minutes and 45 minutes in forward flight. Testing continues along with development of enhanced performance of their 285/290 variants. CFX is now producing their own rotor blades, which are now flying and are developing an engine that will replace the MZ 202 in the XEL and XE models.
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I’m very curious to hear what numbers CFX is measuring.

I have a liquid cooled EMRAX 228 motor in my electric Mosquito, CFX uses the combined cooled motor which can handle 15% more power.

My longest flight so far was 14 minutes which included six climb outs and autos. Motor temperature reached 83C with an OAT of 27C. DA was 1400ft and average motor power about 22kW. From the temperature graph it can be seen that continuous operation under these conditions is possible.

For the same motor temperature the CFX motor will be able to deliver about 3kW more, around 25kW. Unfortunately from measurements I did the tail rotor alone will eat up more than that, my saving grace is that my EMRAX motor does not have to drive a tail rotor because I have an electric tail driven by separate motors.

The CFX machine does have larger diameter rotors (19.5 foot vs my 18 foot) which should give better efficiency. What I have measured though is that the profile drag of the rotors is very high. At zero lift and 540 rrpm the 18 foot rotor consumes 7kW, a 19.5 foot rotor will consume much more. To reduce power the rrpm will need to be lowered, something I can easily do with my aircraft empty weight of 135kg, but unlikely an option considering the weight of the CFX machine.

I will thus be surprised if the motor in the CFX machine will be able to handle a flight of more than about 10 minutes, especially on a warm day.

Another thing is that the inverter in the CFX machine is air cooled and mounted horizontally. I suspect temperature limits will again be reached after about 10 minutes with that configuration, water cooling will be necessary for continuous operation.

The EMRAX 228 is the perfect motor for a lightweight single seat helicopter, especially when running an electric tail. The current CFX machine with conventional tail might just be asking a bit too much from it.
 
DavePA11 said:
Do they have some sort of warning prior to the batteries being drained? Would be nice to have a 4 stroke engine.
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It is only in the prototype stage and a long long way from being put into production but I am sure that there will be ways to show battery levels, something like a fuel gauge. They are in the early stages but are working hard as they always do.
 
The Battery Management Systems (BMS) can be adjusted to give you warning at the "per cell" at any voltage.
The warning systems are easy, I would be more worried about overheating something, or cells failing.
I guess as long as the rotor can decouple and auto rotate it would be salvageable.
I have always wondered how well the small helis auto rotate, it seems like there would not be much momentum in those small blades
and not much time to react....
Are the batteries Li-Ion or LiPoly?
 
I remember forum member Chuck Beaty commenting how impressive it is that the Mosquito could do 20' hovering autorotations straight down to the ground!

The video of it doing so is w/ John Snider @ the controls. He first does one around 4' up, then another around 14', then another @ around 20'. Towards the end of this video, he does a couple from altitude, all the way down on the skids w/ no forward roll:
 
Aerofoam said:
The Battery Management Systems (BMS) can be adjusted to give you warning at the "per cell" at any voltage.
The warning systems are easy, I would be more worried about overheating something, or cells failing.
I guess as long as the rotor can decouple and auto rotate it would be salvageable.
I have always wondered how well the small helis auto rotate, it seems like there would not be much momentum in those small blades
and not much time to react....
Are the batteries Li-Ion or LiPoly?
Click to expand...
Yep, that's what I do. Measure all 102 cells on board and display the lowest cell on the instrument panel. When the lowest cell reaches a certain level (I use 3.3V) a red light starts flashing to tell the pilot it's time to land. I use LiPo, the CFX battery looks like Li-Ion.

Mosquito helicopters aurorotate really well. I've done a full auto to the ground in my electric Mosquito on 18 foot blades, the 19.5 foot blades are even better.
 
Kevin_Richey said:
I remember forum member Chuck Beaty commenting how impressive it is that the Mosquito could do 20' hovering autorotations straight down to the ground!

The video of it doing so is w/ John Snider @ the controls. He first does one around 4' up, then another around 14', then another @ around 20'. Towards the end of this video, he does a couple from altitude, all the way down on the skids w/ no forward roll:
Click to expand...
This was done with Dragon Wing Rotors. In my opinion the success of this design is because of the the rotor system. They showed up at Bensen Days with Rotordyne blades on the first fiberglass prototype body machine and they delaminated overnight in the dew. Dwight and John were pretty upset and disappointed and were packing up I suggested they talk to dad as he had recently built a set of helicopter blades for his personal Mini 500 and I felt he could be a good source of blades for their new personal helicopter that could take the market by storm.

Few years later I was at a flyin at Valkaria and was just looking at a few mosquitos one of the pilots came over and asked if I had any questions. I played along and said I was just checking out the rotors. I was actually looking at the serial numbers to see when the blades were made,since I’m one of the few people who know the code to know when they are were made. He proceeded to tell me that he absolutely loved flying that little machine and it autos as good helicopter he’s ever flown. He said he would put it up there with a Huey or a Bell 404. He was a Army Aviator. Then he proceeds to tell me the funny thing is they are made by some redneck guy over in a Wimauma. He then said I never caught your name. I said I’m Mike Boyette I’m the redneck’s son. Then we laughed and talked some more.
 
The weights were measured in inches. When he first started making the blades for them dad used 4in of brass. Later he switched to 8 inches and all of the Mosquito guys loved the change so that became the standard. Gyro blades came in 4,8,and12in.
 
MikeBoyette said:
The weights were measured in inches. When he first started making the blades for them dad used 4in of brass. Later he switched to 8 inches and all of the Mosquito guys loved the change so that became the standard. Gyro blades came in 4,8,and12in.
Click to expand...

Do you know how to determine which ones you have?
 
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