Hybrid

[John Paris]

I have been trying to make the transition to electric, but am not ready to go all in yet.  Does anyone have a schematic to make a synchronizer so I can keep these two in tune with each other?

[Steve Berry]

Um, April Fool's was like, 2 weeks ago.

Seriously, I have no clue how something like this would be done. First guess would be some sort of active timer for the electric tied to a tachometer that measures the glow engine RPM. Beyond that, I don't know.

Steve

Sent from my SM-N986U using Tapatalk

[Howard Rush]

Start the glow engine first.

Hope this helps.

[john e. holliday]

Glasses>   Not knowing anything about electric I would say individual timers for each motor unless a single timer would drive both.

[Tim Wescott]

I don't know why, but some killjoy put the following into the Control Line Stunt rules "No combination of jet, turbine, electric, or reciprocating engine installation will be allowed."

So, no hybrid setups in competition .  And if you want to submit a rules change proposal, I'll support it. I can't see a reason for that rule -- my opinion on that is that if you really want to shoot yourself in the foot that way, go right ahead.  I certainly don't see any advantage to it (or, for that matter, a turbine engine).  I believe the point of the rules should be to provide a safe level playing field, not prevent people from being creative.

Do you just want both power plants to cut out at the same time, or do you want them actually synchronized in RPM?  The former is certainly easier than the latter.

If you want them actually synchronized in RPM, do you want the slime engine to run naturally with the electric engine slaved (imperfectly) to it?  Or do you want to (imperfectly) slave the slime engine to a constant RPM to match the electric motor?

[Motorman]

If you could get the glow engine to charge the battery that would be cool.


Motorman

[Paul Wescott]

If you could get the glow engine to charge the battery that would be cool.

Motorman

Already been done sir!

https://sullivanproducts.com/product/s660/

PW

[Paul Wescott]

Does anyone have a schematic to make a synchronizer so I can keep these two in tune with each other?

The Wikes TwinSynch has been commercially available for years.  You will have to mount the two sensor setups differently because you have two very different power plants.  I saw one in use at Sepulveda Basin on the RC field.  It was VERY cool when the pilot throttled one engine up and down and the second engine synched up.

https://wikesrc.com/shop/ols/products/twinsync

PW

[Tim Wescott]

The Wikes TwinSynch has been commercially available for years.  You will have to mount the two sensor setups differently because you have two very different power plants.  I saw one in use at Sepulveda Basin on the RC field.  It was VERY cool when the pilot throttled one engine up and down and the second engine synched up.

https://wikesrc.com/shop/ols/products/twinsync

PW

(Smacks forehead).  Of course it's been done!

If you use a spinner model with an aluminum backplate, you can easily mount 1/8" diameter x 1/16" thick rare earth magnets by drilling a 1/8" hole and epoxying them in.  You can epoxy the pickups to aluminum brackets -- then you just have to find a way to mount the bracket.  I've done this on a slime-powered setup and it did fine, so it should also work fine with electric.

[Trostle]

... Control Line Stunt rules "No combination of jet, turbine, electric, or reciprocating engine installation will be allowed."

So, no hybrid setups in competition .  And if you want to submit a rules change proposal, I'll support it. I can't see a reason for that rule

Interesting observation.  Two points:

1.  If one were to propose a change to this rule (Paragraph 2 from the CLPA rule book), to allow the use of different types of propulsion devices, there would need to be a very carefully worded portion that somehow restricts the total propulsion system to some practical and safe level of propulsion.  Right now, total displacement of the reciprocating engine(s) is 15cc (0.92 cu in);  electric power is limited to maximum no-load voltage of 42 volts;  total thrust of any gas turbine is limited to 3.5 kg (7 lb, 11 oz) of thrust.  These limits are imposed for logical safety and "practical" reasons.  If you can come up with a limit to somehow define a practical safety limit for the total hybrid power system that could be installed in a CLPA model, then by all means, do so. 

It would be interesting to understand why you would even want to utilize different propulsion devices in a stunt ship.  If you cannot explain that, then why even bring the subject up other than to show how clever you are that you found something in the rules that you cannot explain?

2.  You found a statement in the rule book that you evidently do not understand why it is in the rule book.  Then you state that if anyone would want to change a change proposal, YOU would support it. BIG DEAL!  If you think that rule is so wrong, then why don't you prepare a proposal to change it.  Just to eliminate the rule completely would not be acceptable to the Control Line Aerobatics Contest Board nor to the AMA people responsible to oversee the safety of our events.

Not that it makes any difference to this discussion here, but there is a similar restriction in the FAI F2B rule book.  This initially appeared in the FAI rule book when the FAI first allowed electric power plants.  We adopted those same restrictions, including the increase to 15cc max engine displacement and allowing electrics when the FAI changed their rules on allowable power plants.  So, I will admit that it was your friendly AMA Control Line Aerobatics Contest Board who is the "killjoy" that included this rule in our AMA rules.  However, it was the FAI F2B rules makers that initially developed this rule.

Keith

[bill bischoff]

I don't know Mr. Paris, but I picked up a "tongue-in-cheek" vibe from the initial post.

[Mike Hazel]

With the hybrid concept, no need for for a battery pack.  Glow engine would drive a generator for the motor.

[Tim Wescott]

It would be interesting to understand why you would even want to utilize different propulsion devices in a stunt ship.  If you cannot explain that, then why even bring the subject up other than to show how clever you are that you found something in the rules that you cannot explain?

Not me.  I think it's a terrible idea in practice -- unless you're really clever you'll just combine all the worst aspects of each power system, and lose the good aspects.  So it's self-limiting simply by virtue of no one winning when they try it.

Why do you take the notion of doing it as a personal attack?

Interesting observation.  Two points:

...  electric power is limited to maximum no-load voltage of 42 volts; ... These limits are imposed for logical safety and "practical" reasons.  If you can come up with a limit to somehow define a practical safety limit for the total hybrid power system that could be installed in a CLPA model, then by all means, do so.

Simply limiting voltage to 42 volts won't limit total power -- power comes from the voltage times the current; if someone really wanted to generate five horsepower with a 42 volt system, all they'd need to do is arrange for a battery pack that can deliver 110 amps or so.  So, nice try.  If you want to limit the total power output, limit the energy capacity of the battery (i.e. rated voltage * rated charge).  That, plus a 6-minute flight time, will limit the power output.

It would be interesting to understand why you would even want to utilize different propulsion devices in a stunt ship.  If you cannot explain that, then why even bring the subject up other than to show how clever you are that you found something in the rules that you cannot explain?

2.  You found a statement in the rule book that you evidently do not understand why it is in the rule book.  Then you state that if anyone would want to change a change proposal, YOU would support it. BIG DEAL!  If you think that rule is so wrong, then why don't you prepare a proposal to change it.  Just to eliminate the rule completely would not be acceptable to the Control Line Aerobatics Contest Board nor to the AMA people responsible to oversee the safety of our events.

So, rule-making is an open and objective process unless you @#$% off one guy?  Why is that?  Can you explain that?  Do you have a certificate that says you're the final arbiter of all the rules?  Do you understand what "open process" means?  Can you explain what "open process" means?  Can you explain how having someone on the contest board scolding people for even suggesting a change fosters an open and fair process?  You're clearly smarter and better informed than me -- so, educate me.

[John Paris]

Everyone,
Thanks to all for the responses and comments.  I briefly considered maybe giving this a shot as I had the slimer on the outboard side and would have taken Howards wise advise to start the engine first but without a good experienced ground crew to help out here did not think it wise to move forward.  This is, in fact, a conversion project that I had planned from some time back on Frank Carlisle's LA Heat.  A recent ride in Jay Williams' Hybrid CRV inspired me to take the shot and Dennis Adamisin convinced me to post it. 

I have completed the conversion and spun the motors up on throttle without props and was happy with the sound of 2 powerplants moving in sync.  The next step was to try it again with propellers.  This exercise helped me rearrange the ESC to give me more battery lead to safely arm the system.  Had this been done from the ground up as an electric many things would have been different but this should be good enough to try out an electric twin for the first time.  Frank's flying style was quite different than mine and the controls are quicker than I normally use. He has some built in slop (at least I believe it is built in) that I have not used before.  The system might be fine and I should find out as the area warms up and dries out.

Some of the specifics of what I have done are 2 Arrowind 2810-1100kV motors, 1 Phoenix Edge Lite 50A ESC, 1 Hobbyking 40A ESC, 2 Thunderpower 4S 2200mAh batteries, APC 10x5E, APC 10x5EP and an RC car receiver so that I can control throttle (simple Y-connector with one positive wire removed after the split).  This all up weighs about 85 ounces and the balance seems okay-maybe a shade tail heavy.  As potential phase II changes, I have a couple of Arrowind 2815-920kV motors (they fit the same motor mount as the 2810s which were modifed to fit the nacelles), some TP 4S 2800mAh batteries if more weight is needed up front or more flight time is needed, another Castle ESC and a Hubin twin motor timer if things seems to work well enough to move on to governed speed and timed flight.  As suggested by Bob Hunt, I also have active timers I could use if I really find the project intesting.

It will just be good to see Frank's airplane fly again as well as trying something a little different in the sport.  I will drop a flight report back after I get a few in.

John

[Brett Buck]

Simply limiting voltage to 42 volts won't limit total power -- power comes from the voltage times the current; if someone really wanted to generate five horsepower with a 42 volt system, all they'd need to do is arrange for a battery pack that can deliver 110 amps or so.  So, nice try. 

    The 42 volts came from the FAI, which in turn corresponds to a proposal to raise the operating voltage of automotive electrical systems to a nominal 42 volts- about what an automotive electrical system would run if you ran 3 lead-acid cells in series. The nominal voltage of an automotive electrical system under charge is about 14 volts - 3x = 42. That also complies with the quasi-standard of either 50V or 60V as the upper voltage limit above which safety shielding or shock safety  considerations are required in industrial or commercial systems.

    But, while you are technically right that you can hypothetically run any current level you want at 42 volts, from a practical standpoint, the size and mass of the conductors and equipment using it becomes prohibitive. So it is a sort of power limit, too. That's why electric cars run at hundreds of volts (Tesla around 400V) and racing cars in the thousands of volts range, and require extensive precautions for electrical shock safety.

   It was my presumption that the FAI adopted the (German, as it turns out - Mercedes) 42 volt standard to preclude the need for electrical safety standards, and to first approximation, a quasi-soft power limit. Note that when this was going around, at about the same time, the other limits were changed (like the limit of a .61 - "10 cc" in French units) to be much bigger. The original proposal for all modeling was originally *250 CC*!

     Their was brief outcry about how dangerous that was, but it very quickly dawned on everyone in stunt that you already couldn't use the full power of even a .40 (maybe 3.5 horsepower if you set it up for it) - what do you think you would do with upwards of 120 hp? The people who didn't get it (Windy, among others) quickly found out why, even a very mildly configured .88 had better have some way to control it that is better than a needle valve and positive vibes. Even the .92 (15cc) might as well be no limit at all.

    Brett

[john e. holliday]

Sorry Howard, the old DOC is the one that needs glasses.

[John Paris]

Everyone,
Vince Bodde came for a visit today and a little flying.  I thought this might be a good time to try out the updated LA Heat.  Power train stayed the same as described with the Castle Creations ESC in aircraft mode and I used a receiver to control things for these first flights.  I opted for 4 cell 2200 mAh packs for these first flights.  I think that the airplane was a tad tail heavy but manageable.  The motors seemed to pull the airplane without much issue and I was able to do some loops, inverted flight (to check battery height for that even run) and some figure 8s to make sure it would all hold together.  Vince put it up once so I could see it from the outside.  Looked pretty good.

More flying to come but for now it was good to see Frank Carlisle's airplane in the air again.  Having worked as his ground crew when it was is slimer mode, I can easily attest that this is a huge improvement in simplicity to become airborne.  Wish Frank was here to give me a hard time about changing his airplane around but at least hope he got to see it from where he is.

John

[Paul Taylor]

Way to go John.
Frank was a super fun guy to hang out with at Brodaks.
Good job on converting the Heat. 👍🏼

[Dennis Adamisin]

This is just crazy cool.  Only saw Franks twin fly a couple times, but never saw a complete flight due to engine problems.  Electrifying it is the only way to go.  85 oz is... intimidating but I'd bet its a blast to fly!