Setup tips for speed flying

[F1 Rocket]

Maybe this can be a sticky so other can easilly find this info. Hopefully other will post what they have learned.

Here’s what I have found on my TDR:
• Use stable main blades that are not more than 225g. Heavier blades will wear out the main grip thrust bearings quickly when running very high head speed. Radix V2, FBL, and Rail are my favorites.
• 95mm tail blades and greatly reduced tail gain works best. Reduce the tail gain as needed to eliminate any tail wag at speed. Also, be carefull when switching to a flight mode that has a higher tail gain setting. Let the machine slow down before you switch.
• HH or Rate mode? I have tried both and can't really tell much difference at speed. In theory rate mode has advantages but you have to trim the tail so the machine flys straight. In practice once the machine is up to speed the tail blades are pretty much running close to zero pitch when in HH mode so there is not much difference.
• A forward CG helps a lot.
• Gear to run the max head speed you want at 100% PWM on the ESC
• More than 15 deg of collective is a waste. It is better to turn the head faster.
• Only the best packs will hold head speed at full collective through the course. Practice with your old ones but save your best for the actual run. If you sense the head speed is decaying a lot back off the collective a bit so the head stays spun up. The worse pitch ups I have had followed a good bog in head speed.
• You need plenty of cyclic travel for the FBL system to work at high speed. I had originally limited this to 8 deg on the HC3-X FBL system. I now run 11 deg with better results.
• The TDR is limited in how high you can run the swashplate and still maintain enough cyclic. On my speed setup I lowered the swash 2mm from the factory spec at mid stick and increased the length of the swash too blade grip links to set the top end positive pitch I wanted. This limits the amount negative pitch but this does not matter unless you fly speed runs inverted
• Good servos are a must but IMO a tight gear train is more important than all out speed or torque. My TDR has 451’s running at 6v and they have not been a problem.
• Keep the canopy holes to a minium. I have a small opening (like the one shown in the TDR manual) on the bottom of the nose. My testing has shown I can get 4 good runs through the course on a 90F day before the ESC gets too hot for comfort. After the first couple of passes the pack has lost it’s edge so there is liitle point in running longer.
• TX expo is your friend  especially on elevator. I also run a lower overal rate on everthing.
• Smooth equals fast. IMO more speed can be gain in practicing then by bolting on more power.

Hopefully this info helps. Please add what you have found. Speed flying is big fun

Danny

[Mercuriell]

Great summary Danny - can't think of too much to add - my slant on flying technique:

- Too much height at the beginning of the run wastes peak pack energy and can run down HS if too much collective is used during the climb

- AT the beginning of the run elevator is used to set up the angle of attack - about 0° nose down then basically isn't touched throughout the speed run - pitch should be at 0° here to allow HS to pick up while the disk is unloaded

- Once the angle of attack is set collective is feed in smoothly - if the initial angle and height has been set correctly the heli will be in level flight at the desired height at full pitch

- At the end of the run collective is bled off before up elevator is applied to prevent violent pitch up and ballooning

- If a ground based radar gun is used to measure speed alignment with the radar gun laterally and vertically is crucial to minimise cosine effect

[F1 Rocket]

Great info John.
I like to fly a shallow, climbing procedure turn (90 deg turn away from the flight line followed by a 270 deg turn to line up on the flight line) rather than a tall stall turn at each end of the run. I may lose some speed without the big entry dive but I have found it is a lot easier for my crappy eyes to see the machine and get it lined up for another run. I let the machine lose altitude through the second half of the turn. This helps it accelerate as I line up for the course.

Danny

[Mercuriell]

Good tip Danny - I am sure the flattish procedure turn - like a boomerang flight, gives the fastest level speed, which is what we are interested in for speed trials, rather than the vertical component, inflated, GPS readings we get from kamikaze dives !

[kimmik]

Very interesting read, all very scientific advice rather than folklore.

[F1 Rocket]

Originally Posted by Mercuriell

Good tip Danny - I am sure the flattish procedure turn - like a boomerang flight, gives the fastest level speed, which is what we are interested in for speed trials, rather than the vertical component, inflated, GPS readings we get from kamikaze dives !

Yes, but the Kamikaze runs are fun too

Danny

[JRAY]

Great info! Thanks! What about other equipment? Main blade size? Motor, ESC?

[GMAURO]

Great post Danny, many thanks! Only one question, why your advice is for set ratio for take desired headspeed to 100% of PWM? My experince is that lower pwm value help governor work, and this is good also for speed.... Or not?

[Mercuriell]

Originally Posted by GMAURO

Great post Danny, many thanks! Only one question, why your advice is for set ratio for take desired headspeed to 100% of PWM? My experince is that lower pwm value help governor work, and this is good also for speed.... Or not?

You dont want a govemor limiting power for speed runs hence the 100%, no need for governored head speed with the disc loaded up at up to 16* pitch! You do need to be careful unloading the disc though to prevent overspeed eg during a mid pitch freefall after a stall turn .....

[F1 Rocket]

Given enough raw available power / ESC overhead it would better to run a governed setup. The 100% PWM advise is more for guys running the average Jive 120 (or similar) setup and helps keep the ESC happy.

Danny

[GMAURO]

Originally Posted by Mercuriell

You dont want a govemor limiting power for speed runs hence the 100%, no need for governored head speed with the disc loaded up at up to 16* pitch! You do need to be careful unloading the disc though to prevent overspeed eg during a mid pitch freefall after a stall turn .....

Thanks for reply Jon, but i don't agree with your explanation. At today i don't have any directly experience on speed flight, but my idea is different, i think that governored headspeed is always better.
Of course, this give more and more "hard work" to ESC and lipo, and what Danny explain is true. But I remain of the view that the governored headspeed is always better.

[marcosp]

Olli uses around 2300 governed at 93% with a Kosmik on the K TDR. He did 148 mph pass!

[jointer]

Properly set gearing will open the ESC up to 100% during FFF anyway, you just will not have overspeed on unload.
So i vote for gov, much more constant feel.

[marcosp]

Exactly!

[joliecoeur13]

how much EXpo are we talking on the Elev. ?

just starting to do some speed passes with my Diabolo , sure is not as easy as it looks ...

would you tame some things down on your FBL unit ?

[FBLessOne]

any advice on fbl settings? specifically vbar?

[jimmy_kubes]

Is it possible to set up a Goblin 700 Competition to do the speed runs? The more I look at things and my style of flying, I lean more to the Speed flying side of the sport. Any recommendations or would I be better off getting another heli?

[jcflyer]

I run gov. at 2300 rpm's and I have reached 140 mph in this setup...

[Djt007]

Good Info

[Djt007]

Great info thanks