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HelicopterMain Discussion › Best endurance gasoline heli?
04-18-2017 06:36 PM  8 months agoPost 21
revmix

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NJ

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

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04-18-2017 07:34 PM  8 months agoPost 22
oldfart

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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

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04-18-2017 07:53 PM  8 months agoPost 23
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

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04-18-2017 09:51 PM  8 months agoPost 24
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

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04-18-2017 09:57 PM  8 months agoPost 25
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

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04-18-2017 10:21 PM  8 months agoPost 26
Pistol Pete

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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~~

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04-18-2017 10:29 PM  8 months agoPost 27
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

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04-19-2017 12:11 AM  8 months agoPost 28
oldfart

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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

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04-19-2017 10:48 AM  8 months agoPost 29
Richardmid1

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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!

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04-19-2017 10:26 PM  8 months agoPost 30
ICUR1-2

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Ottawa, Ontario

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I think Chris Bergen has the best solution

spending time, paying attention

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04-19-2017 10:48 PM  8 months agoPost 31
revmix

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NJ

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

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04-21-2017 05:10 AM  8 months agoPost 32
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

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04-21-2017 05:17 AM  8 months agoPost 33
EEngineer

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TX

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

Logo 600SXs, 800XX, TDR IIs

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04-21-2017 05:27 AM  8 months agoPost 34
Magnumeng

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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

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04-21-2017 05:28 AM  8 months agoPost 35
EEngineer

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TX

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

Logo 600SXs, 800XX, TDR IIs

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04-21-2017 05:29 AM  8 months agoPost 36
Santiago P

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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

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04-21-2017 05:32 AM  8 months agoPost 37
EEngineer

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TX

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Forward or reverse flight?...

Logo 600SXs, 800XX, TDR IIs

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04-21-2017 02:09 PM  8 months agoPost 38
gwright

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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

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04-21-2017 07:52 PM  8 months agoPost 39
revmix

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NJ

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

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04-21-2017 07:59 PM  8 months agoPost 40
EEngineer

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TX

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Will you be there, rev?

Logo 600SXs, 800XX, TDR IIs

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HelicopterMain Discussion › Best endurance gasoline heli?
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