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Champion Q,S and whaterever on the FB
Fast Q


Championship  Q,S and whaterever on the FB

Recently there have been a few streams of discussion on the FaceBook about various aspect of electric. And with the exception of one challenge for E-36/F1S duel at dawn the conversation has been polite and constructive and I hope educational for some new comer.  One was about getting a Electric World Champs and was F1S some how diluting the effort to get F1Q as the “big” FAI FF class to World Champs status.  The short answer is probably not, there are many step that have to be done to create a new World Champs and while there are aspects of Q that people don’t like it is inching in that direction.  There are complications in having a World Champs event and thee are lots of people who Fly e-36/F1S that probably don’t want to mess with that stuff and just has a great time in local or national events.  E-36/F1S is popular, some great kits, excellent entry point but still very challenging for good flyers, so leave it like it is. So that’s enough of that for here for this issue.

So looking a airplane that is bigger than F1S some people think that the current rules with engine run/energy limit favors models with a long motor run that is not very exciting.  So they want something bigger than S but faster.  there are National Rules in a number of countries by these are dated and a serious flyer with a performance model could easily out flyer most sites. So there was a discussion on the FB that is printed below that looks a number of aspects for  it explains a bit about the performance for some of the motors used in  the F5 R/C electric classes  which are many times the power of a F1C so we probably don’t want to use one of those and fortuitousness the last word is from a very positive SEN subscriber who just wants to keep it simple and go fly- that’s fun!


Fast Q

Starter of the conversation : Matti Lihtamo

Several individuals have expressed interest in the electric motor free flight class, which has a faster and shorter climbing time. Would it be a good time to start discussing what this new category could look like? This would probably compete for popularity with F1Q and even F1C. In any case, the future is  time of electric powered models.
– changing surfaces (flapper, folder, sweeper, etc.) are not allowed
– maximum area 34 dm2
– minimum weight 500 g
– maximum motor running time 6 s
What would be desired climbing height? It limits engine power. Restrictive measures could include:
– F1Q-type limiter and determination of available energy
– definition of maximum voltage and current limitation by a fuse or a power resistor between battery and  ESC
Climbing height is substantially affected by efficiency of the propeller. Should maximum propeller diameter be limited to eg 330 mm (13 ”)? In this class, it is important that the model remains at a constant size. Of course, span and other aerodynamic design must be free, as well bunt, wigler, etc. allowed. Before writing precise rules, the specifications should be tested on flying models.


Comment : Jens Larsen
I’m thinking smaller. 180-200cm but 3S. Span would exclude F1A wings but with min 300g auw. With no more restrictions ? would be fun. 600-800W….

Comment : Jack Murphy
Matti- the upcoming NFFS Sympo will have such a proposal that I am writing with critical input from a select group- actually for two classes- one F1C/early F1Q types (bunters) and one for larger locked down models- bigger F1S basically. I am not vetting it on social media because the discussions get sideways fast!!!

Comment : Ray Elliott
In the UK we have an Open Electric class which has different motor runs depending on how many functions the model has. A locked down model has the longest run. I fly a 300 sq in locked down version of a Nig Nog which is pretty competitive. Like a larger E36 as you’re suggesting Jack.

Comment : Ray Elliott
thinking about it isn’t this similar to your Class A?

Comment : Jack Murphy

Ray Elliott
, here is the AMA Electric Rules verbatim- FREE FLIGHT ELECTRIC POWER EVENTS 159, 160, 161, 165, 166.
1. Applicability.
All pertinent AMA regulations (see sections titled Sanctioned Competition,
Records, Section of Champions, and General) and the General Free Flight rules
shall be applicable, except as specified below.
2. General.
A Free Flight Electric Power model electric airplane is powered by a motor that
receives as its sole source of power, energy from electrical current derived from
rechargeable batteries self-contained in the model.
2.1. The following events have been established:
Event 159 F1Q Electric Power (See FAI Sporting Code)
Event 160 Class A – Any number of cells of any rechargeable battery
technology, excluding auto surface models. The limitation on auto
surfaces permits no variable incidence wing or tail, flaps, other restrictions
Event 161 Class B – Any number of cells of any rechargeable battery
Event 165 E-36
2.2. E-36 Model Requirements
36 inch projected wingspan maximum.
120 gram minimum weight, ready-to-fly.
Academy of Model Aeronautics
Competition Regulations | Outdoor Free Flight 28
No auto surfaces permitted. After launch, only one movement
permitted of horizontal stabilizer or wing, for dethermalization
2.3. E-36 Power Requirements
Any type electric motor allowed.
Battery limitations: 2-cell lithium limit or 6-cell NmH or Alkaline
Gearing and folding props allowed.
3. Motor Run/Flight Maximum.
The maximum recorded duration of each flight shall be two (2) minutes, including
qualified fly-off flights.
All models shall be hand launched. Launching shall be as specified for
hand launch of land plane models, FF General.
The length of motor run is to be considered the elapsed time from the
instant of launch to the time when electric power is cut off to the motor.
Propeller braking, or unpowered prop run-down, shall not be considered as
motor run time. Motor runs may be timed only in flight.
Motor Run A Electric B Electric E-36
Flights 1,2,&3 10 seconds 10 seconds 10 seconds
Flight 4 5 seconds 5 seconds 10 seconds
Flight 5 and all
5 seconds 5 seconds 5 seconds
4. Number of Flights.
Each contestant shall be allowed a total of six (6) attempts to make three (3)
official flights. All official and unofficial flights described above are attempts.
Academy of Model Aeronautics
Competition Regulations | Outdoor Free Flight 29
If the three (3) official flights total the maximum allowed, then a series of
fly-off flights may be taken. Fly-off flights may continue until the
contestant’s model fails to reach the flight maximum. Only one (1) attempt
is permitted for each fly-off flight. Fly-off motor run times are as shown in
the table above. Overruns after the third official flight to be automatically
awarded a “0” score.
The CD may at his discretion, add further definitions and/or reduce the
maximum duration limits due to weather, terrain, or local conditions, so
long as adequate notice is given to all contestants before competition
begins. However, flight(s) and flight time(s) flown under CD-imposed rule
deviations shall not to be considered for record purposes.
5. Scoring of Flights.
Scoring shall be the total elapsed time of the three (3) official flights plus the total
of the qualified fly-off flights. Flight duration shall be scored in seconds with all
fractions of seconds dropped. Individual flights that exceed the maximum flight
limit shall receive the maximum flight limit as a score. An unofficial flight is
scored as a zero (0).
Six attempts for the first three official flights are allowed, immediate declaration
required and 20 second maximum for attempts, overruns being automatic attempts
for the first three official flights.

Comment : Jack Murphy
As you can see, Electric B is silent on variable incidence etc so anything goes. A 10 second run is an absurdity. These rules have not been re-considered in some time. As a practical matter people in the US fly their E36s in all three events (E36, A and B). But the early F1Qs that were high powered bunters are legal for AMA B Electric. If there were more participants this is what one would have to fly to be competitive in B Electric. The few who do (Drake Hooke is the paradigm) use a very short run. There are a number of people who fly A Electric- scaling their favorite E36s larger etc. Power packages are self-regulating as it is easy to overpower an electric model but (especially in the case of locked down models) an overpowered model becomes proportionally impossible to trim. A three cell battery requires a lighter motor, 2 cell battery a heavier motor to get into the sweet spot of the desired thrust for a well balanced well behaved model. I have built and flown several locked down (no VIT, auto-rudder, bunt etc just like F1S) in the 350-400+ square inch wing area range and have found that either 1800Kv (approximate) motors with 3 cells or 2300-2500 Kv motors with 2 cells work best in this range. It all depends on which system ends up being lighter in weight or which system helps balance the model easily. In the US you could say it is the Wild West with such open rules, but a great deal of practical knowledge has been obtained.

Comment : Roger Morrell
What you could do is limit the climb altitude rather than energy , like the ALES R/C glider class, for example say max motor run of 6 seconds and altitude at motor cut of 130 meters (or better numbers based experience such as Jack talks about above, its real the principle rather than the actual numbers). The motor run limit would stop the airplane cruising around slowly clocking up flight time and encourage a fast climbing model. This would reward good climb with transition, glide and thermal detection. Not limit energy. ALES altitude limit devices are available. The altitude under power limit could fit with some civil aviation restrictions in that space. … just a suggestion ..

Comment : Roy Dor

Roger Morrell
You will have to use an “anti zoom” algorithm and at the speeds you’re talking about you will have a large overshoot…
It’s not difficult to get a +1kw motor setup for 200-250 grams and after 6 seconds you will have 30+ m/sec climb rate

Comment : Didier Chevenard
Roger. Max weight can limit the potential power of an electric motor which needs in all case copper, iron and magnets to achieve efficiency. I also think that limiting max altitude is a good idea which is already practices in other RC categories

Comment : Roy Dor
Didier Chevenard
Limiting altitude in ALES does not work accurately enough for an FAI class IMHO. If you reach that altitude with high speed, you easily overshoot it. I’ve played with an altitude limiter in F5K and I for a 45 meter motor shutoff I can reach between 45 to 70 meters depending on my models climb pattern and wind conditions.
I currently have an F5J motor, 76 grams including a gearbox. I can pull out of it 650 watts for 30 seconds without cooling. For a 6 seconds of motor run, 1000+ watts is easy. A drone ESC capable of +1000 watts, 60 amps weighs 15 grams including an XT 60 connector and 10 cm of wires. 6s 550mah battery is 100 grams. A 13” carbon prop and spinner is 30 grams. So… 231 grams for a 1000 watt motor system and that’s before trying to save weight by optimisation. So a 500 gram model needs 270 gram structure which shouldn’t be too difficult and a good 30%-50% more power then an F1C engine

Comment : Ed Skorepa
Roger Morrell
Altitude limit device can’t be used with free flight. A motor must be stopped by timer. Otherwise, the Bunt will not work.

Comment : Roger Morrell
Ed Skorepa
the timer can sense the the altitude limiter has cut the motor ( I make timers). The timer also has to have access to the ESC to to stop the motor at the limit of the motor run and in the case of RDT. Also in response to another comment. The… See More

Comment : Ed Skorepa
Roger Morrell
“The timer can sense the altitude limiter has cut the motor (I make timers)”. Good job on your timers! My F1Q Sidus can’t sense the altitude. However, it has access to the ESC of course.

Comment : Matti Lihtamo
Ed Skorepa
, Also, my timer FT6 does a bunt according to the stop information sent by the limiter.

Comment : Ed Skorepa
Matti Lihtamo
Is it available?

Comment : Matti Lihtamo
Ed Skorepa
, This during the spring. We will release it with a new limiter.

Comment : Matti Lihtamo
Here is the previous version. Light and compact, card 33x21x5.6 mm and weight with wires and connectors 5.6 g.
No photo description available.

Comment : Jukka Juslin
Matti’s question about climbing height is interesting and I suppose important. Would be nice to see some answers to that? I have some suggestion, but maybe do not dare to put it here.

Comment : Alexandre Cruz
F5J penalizes altitude. That in my opinion would be a game changer and make things a lot more interesting

Comment : Roger Morrell
The discussion is good as it it bringing out a lot of information. A question is what is the objective ? I think the answers is to have a fast climbing FAI electric class that is a bit bigger than F1S/E-36. Roy Dor
gave us very useful input. He compared power output with a current F1C model. We know that the performance of a current F1C class is already too high – The Current World Champ Taron Malkhasyan
did 6 seconds under 10 minutes in a dawn flyoff in perfect conditions at Lost Hills off a 4 second engine run. Others above have proposed rules forbidding variable camber, variable area wings that are partly responsible for the high performance of the current F1C. Not sure how high a current F1C gets – ? Taron Malkhasyan
? 150 + meters? But clearly we do not want a motor that is whole lot more powerful than a F1C one. So the issue is how to restrict the performance in a way that is easy for the contestant and organizer. F1S restricts it largely by the air frame – size, weight and no automatic surfaces. Currently we use the energy limiter in Q – this has some big side advantages in that the energy allocation can be reduced to match the weather or visibility. Another mentioned was the Kw of the motor. both of these require some measure device that is more sophisticated ? than a micrometer. From what Roy said we probably want some on top on just altitude and motor run time if we took that approach

Comment : Taron Malkhasyan
Roger Morrell
130-150 meters is the target range throughout the day. It only took 145 meters to do the 10 minutes

Comment : Roger Morrell
Taron Malkhasyan

Connent: Derek McGuckin
Keep it simple- 2 Meter wingspan. 10 sec or less motor run. 100 meter altitude motor cutoff (could be higher on a big field) Minimum weight if needed. Have fun!

The actual conversation is here –