Speed Talk

[Barry Tilson]

Wanted to talk speed. Would like to try some speed runs this next year. I have a bunch of questions related to the setups, safety and how it's done. 

First question how do you know when your going to hurt something? I.E. Puff a set of lipos over draw a system?

Do you ease in to it with ESC data logging? Keep upping your gearing until you've maxed out your system?


Barry

[Matt Botos]

I'd consider myself an intermediate speed guy, not a professional speed guy by any means. I have learned from a few of my own mistakes as well as paying attention to what the serious speed enthusiasts are doing. I've done 129mph with a stock E7, 119 mph with an E5 stretched to 600, and 94 mph with an N5c. I am trying to break into the high 130's which is proving to be harder than it seems. Here are some of my suggestions based on past errors and success.

1. Bullet Connectors - Make sure your bullet connectors are making good contact. It doesn't matter if you are using the biggest bullet connectors on the market, if they are not making a good connection then your connectors will heat up and potentially melt your solder. Bad things happen after that.....

2. 12s is good but things tend to heat up much faster than 14S

3. Good equipment - everything from high quality/high discharge batteries, to the right servos will make all the difference in the world. You can't skimp on anything if you want to go fast and have your helicopter stay alive.

4. FBL System Configuration - The FBL unit needs a bit more cyclic overhead in order to achieve full pitch at 15-16 degrees and still have enough elevator left over to keep it from pitching out. This has been one of my biggest challenges. Also consider a high torque cyclic servo (above 300 oz-in) to help the elevator hold in high speed forward flight.

5. Gearing and Motor Selection - Select the correct Kv Motor and gearing for your head speed need. I like to keep my gearing as close to 10:1 as possible for mechanical advantage. This will keep everything running as efficiently as possible.

6. Piloting technique/skills - Don't slack on this one, speed piloting is not easy! Holding a straight line at 130+ mph can be very difficult.

That's all I have for now... hopefully some seasoned speed guys can come in here and give some tips.

Thanks!

Matt

[Chuck Bole]

 Getting drag to a minimum is important as well. Danny at Esprit suggested running smaller tail blades.
I have a set of 96's tails i am going to try. As well as putting the tail in rate mode or FC3 on the CGY 750.
I also plan on using a E5 cross brace at the rear of the frames to put the boom supports inside the frames.
Also colors play a big part. The heli gets pretty far away and a little difficult to see. At least for me anyway.
Having the CG a little forward will help from robbing power by using cyclic to keep the nose slightly down in forward flight.
If you want to run the speed traps at IRCHA, a long runway or flight line to practice is a must in my opinion.

E7
Scorpion 4530 450
YGE 160 HV
Rail 716 / 106 / 96
BLS 255's and 256
CGY 750
TP 14s 4400 65C
Secraft HV BEC

chuck

[Chris Sexton]

2013 Speed Cup was my first official running of a Speed race, and let me tell you, I wasn't ready! Pilot skill is such a big part of it. Holding the course and not bleeding off speed with unneeded corrections is harder than it sounds! The FAI Speed regulation course is BIG, way larger than I expected seeing the numbers on paper.

My setup this year will be a bit different than last year.

E7se
Scorpion 4530-450
Scorpion 160a 14s ESC
Scorpion Backup Guard (want to keep the weight down so I am running a BEC, but still need some help if the BEC melts down)
RJX FS-0521HV Cyclic @ 8.4v
RJX FS-0521THV Tail @ 8.4v
Rail 716 mains
Rail 96 tails
iKON
Thunder Power G8 14s 4400mAh stick pack
WR Super Hercules BEC @ 8.4v
No Gov, flat 100% throttle curve
17 degrees of Collective, 8 degrees of cyclic with lots of expo
And of course, my Rob Cherry, Ben Kerr custom skids

My Canopy is BRIGHT Orange and Red, very easy for eyes to see at a distance. I also re-positioned the boom supports to help with drag. Tail fin is mandatory, but i am going with a Solid fin to reduce drag on cut outs. I will also likely change the shape of the fin a bit.

Last spring I played with a custom hand laid fiberglass fuse, but I could never get it right and we ultimately broke it.  I am going to try and stay in the Stock class, or at least was used to be known as stock. New classes still have me baffled.  My goal this year is 125+ I am sure this machine can do better, but again pilot skill is alot!

[Anthony Oxlade]

Chris,

Could you share a few pics of this speed machine? What are these custom skids like?

cheers

Anthony

[Chris Sexton]

I don't have it together enough to take pictures, having to reconfigure a bunch. When this picture was taken it was stretched to swing 753 mains.

But here is the canopy and skids. I am hoping Matt's speed canopy makes it to market in time to repaint one bright orange.

[flyalan]

I was privileged enough to see the speed canopy in action at Clint's Bash.  Not sure if you will need to paint it orange Chris!  Pretty darn visible as is...  And you know me and canopy's 

Cheers

Alan

[Chris Sexton]

I was privileged enough to see the speed canopy in action at Clint's Bash.  Not sure if you will need to paint it orange Chris!  Pretty darn visible as is...  And you know me and canopy's 

Cheers

Alan

That is great news indeed!!

[Chuck Bole]

 What we need is light weight, but stout enough retracts. I swear i seen a FAI heli years ago, maybe Scott Grey if I remember right. But the skids retracted up into recesses in the bottom of the canopy.

 Anyway,  I've been debating with myself on tail rotor ratios and blade size..

 So at a head speed of roughly 2300 and a tail ratio of 4.5, that would put the tail rotor at 10350 RPM. Ya think 96 tails would be enough for 716's at that RPM? I'm not planning on any aerobatics except maybe the 1/2 Cuban 8 turn with this machine, just strictly speed runs. I think i can play around with tail ratios some. Just looking for some ideas.

chuck

[Mike King]

Yep, that was Mr. Grey with the retracts into the fuse.  Very very cool.

[Chuck Bole]

 So now that the speed canopy is public, lets get some talk going here.
Alan, I've ran the Scorpion 4530 450 motor for awhile now.  With a YGE 160 and 14s 4400 packs.
Just recently went to a 13T pinion. What have you done as far as tail gear ratios? I went back to
the the standard ratio 54T/12T on the tail and tried 96 tail blades. Seems to hold the tail fairly well.
What are everyone else's thoughts?

chuck

[Barry Tilson]

I picked up another E7 with a x-era 4530-500 and a kosmic. May set this one up for some mild speed runs. Not sure if this motor can go 14s?


Barry

[Chris Sexton]

No that exra isn't rated for 14s

sent from my Verizon Samsung Galaxy Note 2

[Chuck Bole]

 I ran a X-era 4530 on 14s a few years ago for the IRCHA speed runs. It got a little warmer and didn't really give me that much more power IMO. David Bloomfield ( the X-ERA designer) PM'd me this about running it at 14s on a full charge.

CNCAddict wrote on 08-02-2011 12:49 PM:
Hey Chuck,
The 4530 should be fine on 14s although it'll run a little warmer. @3.7V/cell and 10.3:1 it would give you 2514rpm at 100% or 91% throttle for 2300rpm. Need to be careful at full charge not to go to full throttle since that would be 14*4.2*500 / 10.3 = 2854rpm.
Thanks,
David B.

 
 
 I'd creep up on it if i was doing it again. I blew up a fairly new set of 7s packs practicing runs on Thursday before the event on Friday.

chuck

[Chuck Bole]

"Always fly as fast your Machine can handle safely  and as fast your brain can process it "

 Ain't that the truth!

chuck