First introduced in Europe in 2013, the all aluminum single seat enclosed cabin Merlin LSA has sported a variety of engines, including a Rotax 582, a specially built four stroke V-twin and even an electric motor. In fact, the Merlin airframe has served as a test bed for all kinds of propulsion and aerodynamic innovations. At AirVenture 2023, Aeromarine chief designer Chip Erwin even showcased a Merlin model with twin propellors imbedded in the wings. Erwin promises an even bigger surprise at Oshkosh later this month: a common-sense hybrid propulsion system for the Merlin.
Erwin, who has done work for the Air Force Research Lab in Dayton, Ohio, has developed a parallel hybrid drive system for light sport aircraft that utilizes an electric motor to add to thrust generated by a
The electric motor is built into the belt reduction drive!
piston engine during takeoff and climb, but shuts down during cruise. He points out that a major limitation of all electric aircraft is the need to lug around a heavy battery capable of providing thrust for a limited period of time. The advantage of a piston engine is that it can provide the reduced thrust necessary for cruise flight in a lightweight package, utilizing a relatively small amount of fuel.
A typical flight plan for the hybrid system would entail using the piston engine, supplemented by the parallel electric motor, to provide the combined thrust necessary for takeoff and climb. Once a cruise altitude is reached, the electric motor would be shut down and cruise would be accomplished on the piston engine alone. Erwin points out that the electric motor would be free wheeling during cruise flight (through the use of a sprag clutch) resulting in insignificant drag to the thrust produced by the piston engine.
This parallel thrust setup allows the use of a smaller, lighter and more fuel efficient piston engine, supplemented by a light weight electric motor. Since the electric motor is only used for takeoff and climb, it utilizes a fairly small battery, which is recharged by the gas motor during cruise. Formula One race cars have been utilizing this concept for the past several years, using a small but powerful electric motor to provide added torque for critical phases of each race such as the standing start and powering out of corners. The Formula One batteries for these cars are the size of a laptop battery, discharging their energy for relatively short bursts and being recharged on the straights.
The electric motor components of the drive.
The parallel hybrid system is designed to provide greater efficiencies for light sport aircraft, resulting in lighter weight and increased range. We should be able to see it all in person at Airventure, where Erwin promises an impressive display.
Is there any information about the Merlin Lite that crashed in Florida about a week before Sun n fun this past spring.
Best to ask the source. Aeromarine LSA.
I too have have been waiting for nearly 4 years for the electric Merlin lite with extended wing model to start selling, but I won’t buy one until I see some satisfied owner feed back. Soon I will not be capable of flying anymore. Should have bought something else while I still had the good health to fly.
Deberias comprar un biplaza convencional para invitar a algun amigo mas joven que quiera volar y sacarte a dar un paseo.
(computer translation) You should buy a conventional tandem to invite a younger friend who wants to fly and take you out for a ride.
It is one thing to come up with inovative ideas, another to build a successful prototype, then quite another entirely to actually manufacture and sell production models. Has anyone ever been able to buy one of this guy’s airplanes??? I haven’t heard of any. They are always “just around the corner”
I’m not a doubter, but I am a skeptic.
I would be curious to see the all-up weight of the hybrid system (Engine, Motor/PSRU, motor controller, and batteries), as compared to a diesel of the same output. Obviously one would have to take into account Cruise Power, METO and TO power (since the motor provides only a performance boost for T/O and initial climb).
As there is no real data in the article or the AeroMarine web page, it would be difficult to do more than SWAG* at this point.
* Scientific Wild Assumed Guess.
I think this will probably be the next logical step for small planes since battery-only aircraft will have too short of range in the foreseeable future. Combining a smaller engine with an electric motor could result in meaningful fuel savings / extended range. The other advantage I see is safety – if the gasoline engine fails, the electric motor should give the pilot extra time to make a safe landing.
P Clark, not sure what is being said here? Are you saying this engine would be great as a auto unit used in a airplane? in your opinion, or that the prius should have a bigger tank. The later is already delivering two or three times a bladder capability.
Also, when you say on the cheap for the engine? do you feel you can reliably get said engine PLUS the electronics to make it run well all done easily?
Just curious.
tal vez de esta forma complementaria podrian los motores electricos ser mas eficientes que los alternativos, creo que aun hay mucho camino para desarrollar motores con combustible. Una vez que subes a una altitud de crucero ya pesa menos por el combustible consumido, en cambio las baterias siguen pesando igual con carga o sin ella
Translation:
Perhaps in this complementary way electric motors could be more efficient than alternative ones, I think there is still a long way to go to develop fuel-powered engines. Once you go up to a cruising altitude it already weighs less due to the fuel consumed, however the batteries continue to weigh the same with or without load.
Here is a factual info to consider.
I have a 2014 Toyota Prius car I bought new , love it , gets great gas milage . I can fill the tank right up to the fill spout so I can’t get any more gas into the tank. Than I can set the cruise to 68 MPH and go well over 650 miles distance. At that set cruise speed of 68 MPH , I get 54.6 MPG
Now think about this. You are carrying only 12 gallons of fuel ⛽️ takes you 650 miles @ 68 mpg. Why not modify a 100 hp Prius motor you can buy in any salvage yard cheep money . And carry 25 gallons of gas would take you 1200 miles.
AND , all these Toyota Prius engines are bullet proof too. They use mobil -1 synthetic oil and go well over 300,000 trouble free miles. My friend has a taxi service business . She just sold three of her older Prius cars with over 300,000 miles on each car , all still going strong.
SO. Here is a very solid , dependable solution for a very dependable , reliable modified aircraft engine. AND ready available repair parts as well thru your local Toyota dealer as well.
The Prius power train (engine, electric motor and battery) are quite heavy. You would also have to come up with a PSRU plus a cooling system adding more weight.
The advantage of a hybrid car is regenerative braking which is not available in flight. Even Joby Aviation has gone to hydrogen-electric (fuel cells) because all battery power is not practical in aviation. The idea of adding an electric motor to the drive is not new. There is a reason why the attempts have never worked out.
Chip is great at developing new products, but does he deliver any? I have been waiting almost 3 years now since I signed a purchase agreement and made a down payment on a Merlin Lite! How many other people are waiting for an order to be available? My faith is starting to wear out!
Three years? Does he offer you any reasons for the hold up?
This is a great idea. So great I had it maybe 9 months ago, but never did anything with it.
Chip is always thinking out of the box. It was just last week my wife asked me why no plane manufacturers produced a hybrid, like the Toyota Prius was. Given this, I sure wish he would concentrate on that two seater! That would sell better than than this.