National Free Flight Society

SEN 2081

Table of Quontents – SEN 2081

  1. Biggles was right on
  2. Q OK
  3. Q not that hard
  4. Change Q

Agreeing with Biggles on F1Q and E-36 vs F1S

From: Stan Buddenbohm
Biggles was right on with his analysis about the reason for lack of popularity of F1Q as presented in SEN 2080.

There is one misunderstanding that seems to be perpetuated around the world though: That E36 and F1S are the same, they are not. The model requirements are the same but the flying requirements are quite different and are the reasons that F1S has had miserable participation in the U.S. F1S requires increasing length of flyoff flights. Most E36 competitors do not like this, too risky at most fields. F1S often requires a “Champagne flight” to the ground, no limit, to be used as a tiebreaker after a number of flyoffs. Again this risks the model unnecessarily. F1S must be flown in rounds, the five regular rounds require a 10sec motor run and a two minute max. A good E36 will do 3 to 4 1/2 min with a 10 sec motor run and no thermal, these rounds are boring. Finally E36 flyers are often flying other events, in the U.S, and are unwilling to travel out to the FAI flight line for each round.

Stan Buddenbohm


From: David Ackery
I have to come out in support of Per Grunnet and his thoughts on F1Q.

He is spot on with his analysis, the use of the energy limiter is the only
sensible way to fly this event. And what has held back F1Q so far is the
people who don’t understand this, and have attempted to use the wrong
parameters (like motor run) to define what can be done. There is no motor
run limit in F1B because it is not needed. (People have been known to use
F1B prop runs from 20 to 80 seconds, you get to choose/use whatever you

“It is correct that you have to learn a thing or two about electricity if
you will fly F1Q. But not more than most of us learned in school ,,”

“Energy is measured in joule ,,In F1Q the joules are stored in the battery –
and when the allowed number of joules have been sent to the engine, the
energy limiter cuts of the engine. “.

This is so simple, and so logical. I am sure that just about anyone can
understand it, you don’t need to be an electrical engineer.

best regards
David Ackery

Give F1Q a chance – it’s not that difficult

Brawn David, thank you for your reply about E36 and F1Q. You express views
that are shared by many – which does not necessarily mean that they are

When discussing F1Q it is important that you understand, what the energy
maximum rule is about. In short it says, that the model can use a maximum
of 4 joules of energy per gramme model weight (for model weight up to 500
grammes) in each flight. The energy comes from the battery. You must
determine the energy use and cut the engine, when the maximum energy is

This can be done in two ways:

You can measure the energy use statically to find out how long it takes
before the maximum energy is used (the motorrun must be timed in full
seconds, so you will lose between nothing and one seconds motorrun, if you
measure the energy this way). The F1Q-rules tell how to measure the energy
use – it is not difficult, you just need a wattmeter and a stopwatch.

The second way is to fly with an Energy Limiter. The limiter cuts the engine
at the exact time, when the energy maximum is reached – with a limiter you
can use every joule you are allowed to. Energy Limiters can be built
(instructions can be found on the internet) or bought. There are several
suppliers around the world.

In F1B – as you write – there is much difference in performance depending on
what kind of rubber you use. This means that getting the best rubber is a
part of the game in F1B. The parallel aspect – getting the best battery – is
not as important in F1Q because of the energy rule. In Q you don’t have to
use extremely light and powerful engines or batteries – you can choose
heavier, less expensive components, because you will get extra energy for
the extra weight – and still be competitive.

The rules states a way for contest directors to control that the competitors
in F1Q only use the allowed energy. The control is easy to perform and only
requires a wattmeter and a stopwatch.

One last thing: A fixed engine-run is not a practical rule for F1Q. It will
favour fliers, who are willing to ruin a LiPo-pack in each flight, and who
are able to buy very specialized engines. The class would in short time have
the same problems as F1C has today. The energy maximum rule allows very
different models and flight patterns to compete on equal terms. Very
fascinating in my opinion.
Per Grunnet

From: Don DeLoach

Five years ago the NFFS Electric subcommittee created modern E-36. The first year at the U.S. Nats, 2011, there were seven flyers. This year there were 45, making it the popular event in the country.

Want to make F1Q the most popular FF event on the planet within five years? Adopt the following rules:

3 cells Lipo maximum.
No area, motor, prop or weight restrictions.
No variable geometry.
7 rounds, 10 second motor run, 180 max
Flyoffs at 10 sec, max: 300, 420, unlimited

–Don DeLoach

Roger Morrell