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HelicopterMain Discussion › Best endurance gasoline heli?
revmix

Key Veteran

NJ

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best endurance gas heli per ounce of fuel
depends on the take-off weight of the machine

04-18-2017 06:36 PM
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oldfart

rrProfessor

Vancouver, Canada

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depends on the take-off weight of the machine
That does have some effect But the biggest factor on any heli will be the rotor speed it is set to turn at.

If heli A is 10% heavier then heli B, it will have a fractionally less fight time.

On the other hand if Heli A can hover for 6 minutes on a 12 oz. fuel tank and has a 10% higher head speed (say 2200) and Heli B has a lower head speed of 1980, then heli B will have a 35% longer flight time on the same 12 oz. of fuel. (about 8 minutes)

Now bring the Heli B head speed down to say 20% (1760) and it will have a 70% longer flight time (about 10 minutes).

What will suffer, will be the cyclic and collective response times...but not necessarily by the same ratios if one is able to increase the collective and cyclic pitch ranges.

Phil

04-18-2017 07:34 PM
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revmix

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NJ

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yeah, but higher RPM-headspeed needs less pitch to maintain height & air speed & the OP's concern was for fuel consumption

04-18-2017 07:53 PM
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ssmith512

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Indianapolis, IN USA

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yeah, but higher RPM-headspeed needs less pitch to maintain height & air speed & the OP's concern was for fuel consumption
Curious, what causes more drag: Airfoil with low angle of attack and high rpm (airspeed), or same airfoil with higher angle of attack (required angle of attack to maintain same lift as aforementioned lower angle of attack) but lower rpm (airspeed)?

Steve

04-18-2017 09:51 PM
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gwright

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Champaign Il

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lower rpms, higher angle of attack is better for efficiency, if your only concern is lower average power .

Gary Wright
Futaba
Flightpower
Prod manager at Hobbico

04-18-2017 09:57 PM
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Pistol_Pete

rrProfessor

Seffner, FL

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Wow...This thread almost read like the gasser forum 10 years ago but with new players.

Ok, I have nothing to contribute. Back to clashing.

~~Enjoying the hobby one flight at a time~~

04-18-2017 10:21 PM
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revmix

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NJ

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the biggest factor on any heli
gross weight is major for lift & velocity regarding energy

04-18-2017 10:29 PM
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oldfart

rrProfessor

Vancouver, Canada

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Here is a simple test anyone with a heli can do.

Let us say your heli weighs in at 7 pounds (112 oz.). and hover for the tank or battery down to 80% of battery capacity. Check the time and the rotor speed.

Now attach a weight of 10% (11 oz.) to the cg (a good place is on a plate attached to the bottom of the frame right under the main shaft). Now fly as before and note the time.

Now take the same heli, without the weight, and drop the head speed by 10% by adjusting (dropping) the throttle settings, and increasing the pitch, so that it hovers. Now hover out the tank or the battery pack as before. Now note the time.

Which made a bigger difference?

Note this is all with the same heli, using the same blades.

I know, as I have done these types of tests many times.

Phil

04-19-2017 12:11 AM
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Richardmid1

rrProfessor

Leeds, England

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Maybe with increased cooling and with the lower engine rpm you can run much leaner increasing flight time?

60% of the time, it works every time!

04-19-2017 10:48 AM
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ICUR1-2

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Ottawa, Ontario

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I think Chris Bergen has the best solution

spending time, paying attention

04-19-2017 10:26 PM
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revmix

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NJ

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best solution
must have big tank/s for lotta ounces of fuel

04-19-2017 10:48 PM
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Santiago P

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South West, Ohio

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So let me get the cat out of the bag,

I am creating an endurance event for the IRCHA Jamboree.

It will have electric and ICE classes,

I am trying to figure out simple rules to let anyone participate, but not discourage innovation.

The main goal is to have fun!

Minimum heli weight: TBD

Electric: limited to XXX amp-hr
Gasoline or diesel: XX ounces

All helis: 90 seconds to get in the air.

Heli will hover between 6 and 15ft height (roughly), in their parcel/station

last one to stay in the air above 6', under power, wins.

2 pilots per machine taking turns is permitted (it could be a long ass hover for one person)
This is all preliminary.
More details to come.

Santiago

04-21-2017 05:10 AM
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EEngineer

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TX

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Aha! I knew something was up......

Logo 600SXs, 700XX, 800XX

04-21-2017 05:17 AM
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Magnumeng

Veteran

29 Stumps, CA

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Great idea.. to add more excitement to... how about have them all fly in a figure eight pattern... so not only must they battle the gas/battery limits... they have to watch out for a midair...

TDR, Kontronik Kosmik Cool 200, Kontronik 750-56, CGY750,
Team KBDD

04-21-2017 05:27 AM
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EEngineer

Elite Veteran

TX

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Or a "payload" event for the gas hogs....

Logo 600SXs, 700XX, 800XX

04-21-2017 05:28 AM
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Santiago P

rrProfessor

South West, Ohio

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Figure 8 track

That will be the following year's event!

Payload: I thought about that too, it would be the same for both electric and gas.
That seems to be a very good task, but I'm incline to add to next year and just do plain heli for the 1st time.

BTW, no figure 8 track, the AMA would never let that happen

S

04-21-2017 05:29 AM
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EEngineer

Elite Veteran

TX

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Forward or reverse flight?...

Logo 600SXs, 700XX, 800XX

04-21-2017 05:32 AM
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gwright

Veteran

Champaign Il

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i LOVE this idea Chago! Of course ideas started floating around in my head about rules suggestions and such, then I realized to encourage participation it would have to be very very simple. Maybe just weight and energy capacity. Weight is easy with a scale, energy capacity easy with electric, just require the manuf. label to be on the battery, but with gas and glow you'd have to have some way of measuring the fuel load. Shouldn't be too difficult. then it all boils down to efficiency in the setup which is obviously the goal.

Gary Wright
Futaba
Flightpower
Prod manager at Hobbico

04-21-2017 02:09 PM
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revmix

Key Veteran

NJ

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power to weight ratio; ~200W per kg @ standard sea level air-pressure (29.92)

04-21-2017 07:52 PM
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EEngineer

Elite Veteran

TX

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Will you be there, rev?

Logo 600SXs, 700XX, 800XX

04-21-2017 07:59 PM
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HelicopterMain Discussion › Best endurance gasoline heli?
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