RunRyder RC
 2  Topic Subscribe
WATCH
 1 page 714 views
Scorpion Power Scorpion Power
HelicopterCentury Radikal G20-30 N640 Hawk Predator › Header Tank Location Question
12-24-2008 03:56 PM  8 years agoPost 1
CompyMike

rrVeteran

sacramento, ca

My Posts: All  Forum  Topic

I went from the older plastic side frames on my Hawk 3 to the hawk Pro metal frames. I had my header tank mounted infront of the main tank so the outlet of the header tank was almost inline with the carb. There is room with the plastic frames to do this. But now with the Pro side frames I can't do this. Looks like I will have to move the header tank quite a bit higher and I am wondering how much this will effect my mixture. When I went with the hawk pro frames I didn't put the header tank back on and test flew it and it seemed that the mixture didn't change at all with just the main tank. But I like the extra security of using a header tank. And it looks like people put header tanks on hawk pros up behind the main tank. Is this going to make me run alot richer?

One thing I read is that with the header tank above the carb you run richer when you empty the main tank and just feed off of the header tank. But if the header tank is at or below the carb then you go lean when you hit the header tank. When I had the header tank infront of the main tank and pretty close to the same level as the carb I ran lean when I hit the header tank.

So I guess my main question is...
does the location of the header tank effect the mixture when both the main and header tank has fuel?

Mike

PM  EMAIL  GALLERY  Attn:RR  Quote
12-24-2008 04:07 PM  8 years agoPost 2
Dr.Don

rrVeteran

Cedar Park, TX --​USA

My Posts: All  Forum  Topic

Depends to some degree on what engine you use. If it is an OS with muffler pressure, the mixture will change some as you change attitude if the header is significantly higher or lower than the carb. If it is a YS with a sealed pressurized fuel system you won't see much affect. The YS pressurizes the whole system to several psi, so the variation of pressure with attitude of the heli is pretty small by comparison. At least this is my experience.

Dr.Don

PM  EMAIL  GALLERY  Attn:RR  Quote
12-24-2008 04:12 PM  8 years agoPost 3
CompyMike

rrVeteran

sacramento, ca

My Posts: All  Forum  Topic

It's a OS32 and using the muffler to pressure the fuel.

So I guess it will go richer.

PM  EMAIL  GALLERY  Attn:RR  Quote
12-24-2008 07:22 PM  8 years agoPost 4
beavis1

rrKey Veteran

New York state

My Posts: All  Forum  Topic

The general terms you refer to are correct.

You really see it more due to the motor. That OS 32 has real poor fuel draw so even when the header is even you still lean a bit unfortunatly. If it is used then draw also goes down from there from bad to terrible.
Setting a touch rich and letting it come in some times is the lesser evil.
Putting a clunk on the pressure line works well. It does somthing having the pressure come out in the fuel that I have seen exsplained a dozen times but it works. It may not be enough for the os 32 though.

You can also run the perry pump with the curtis flow back and it works as well as a YS system. Keeps it 100% the same the entire flight. In his FAQ section he has a diagram it was designed for the os 90 but works on 50 and 30 models also.

The OS 37 has radicaly improved fuel draw as well as the toki motors. They run well without a header.

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
12-25-2008 04:56 PM  8 years agoPost 5
Dilbeck

rrElite Veteran

Springdale Arkansas

My Posts: All  Forum  Topic

Mounting it up and behind the fuel tank it will go rich when the main tank emptys and you will be able to here the differance, This is OK though because you will know when to come in and land and the extra cooling always helps.

Clint

PM  EMAIL  GALLERY  Attn:RR  Quote
12-27-2008 11:56 AM  8 years agoPost 6
CompyMike

rrVeteran

sacramento, ca

My Posts: All  Forum  Topic

Thanks Beavis.
I had a successful maiden with this hawk today and did some long flights. I did notice a reduction in power as the fuel went below a half a tank. I might try the uniflow system. I had it hooked up when I was first putting this heli together. Makes it run richer.

But the OS32 doesn't have that reserve amount of power to get me out of trouble so I fly it very cautiously. I think I might start hunting for a OS37. I have a OS46 FX but I don't hear anything really good about those motors. And I would have to change gears.

PM  EMAIL  GALLERY  Attn:RR  Quote
WATCH
 1 page 714 views
Scorpion Power Scorpion Power
HelicopterCentury Radikal G20-30 N640 Hawk Predator › Header Tank Location Question
 Print TOPIC  Make Suggestion 

 2  Topic Subscribe

Monday, November 20 - 11:11 pm - Copyright © 2000-2017 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online