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From: Bulent Aliev <atlasyts@bellsouth.net>
Subject: Re: [FlyRotary] Re: Tips on tuning
Date: Fri, 3 Aug 2007 20:09:17 -0400
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>

Dave ,
 =46rom what I have read, flattening the pitch will get you RPM and =20
power, but your forward speed will suffer.
Same like revving your engine in 1st gear.  Prop with diameter like =20
ours should be spun at around 3K RPM for best performance
on takeoff. With my reduction drive 2.17 this prop RPM also brought =20
my engine at it's best power RPM at 6.5-7000 RPM
I may be wrong, but it worked well for me.
3 blades used to bring down my engine RPM to 5200 and the prop to =20
around 2400. which was not that good?
Again, I'm just an eyeball engineer and not a guru on the subject.
Buly
Still hang'n around :)

On Aug 3, 2007, at 6:53 PM, David Staten wrote:

> Lugging? Was this full fine? or at a coarser setting?
>
> I'm all for 3 or more blades because there is more surface area to =20
> impart thrust from. Since we have a prop disc limit of 66 inches on =20=

> our airframe, adding blades is the way to go to improve thrust. =20
> There is a limit to the amount of HP a given blade can absorb and =20
> transmit. I wouldnt necessarily be opposed to trying a 6 blade =20
> variant either, provided we are making full power with our engine, =20
> or later with the turbo.
>
>
> Dave
>
> Bulent Aliev wrote:
>
>> I used to have the same prop as Chris IVO Magnum 68" Diameter  =20
>> inflight adjustable. I felt the 3 blade configuration used to lug =20
>> the  engine down. Changed it to two blade (did not want to cut =20
>> the  blades). My takeoff RPM was 6,500-7000.
>> Buly
>>
>> On Aug 3, 2007, at 4:15 PM, Mark Steitle wrote:
>>
>>>
>>>
>>> On 8/3/07, Al Gietzen <ALVentures@cox.net> wrote:
>>>
>>> Al,
>>> I think Chris B. brought this up earlier today.  I didn't =20
>>> respond,  but you mentioned it, so then couldn't resist the urge =20
>>> to comment.   To refresh everyone's memory, I have a 20B with a =20
>>> 76" 3-blade  constant-speed M/T prop.  So, I can dial in the prop =20=

>>> speed desired  and the prop controller does the rest.  With it =20
>>> set to 2500 rpm,  I'm seeing 7000 engine rpm on takeoff rolls.  =20
>>> (What a sweet sound!   It makes those Lycosaurus' sound like farm =20=

>>> tractors.)  It will turn  about 6700 - 6800 during static =20
>>> runups.  But this is a c/s prop, so  your mileage may vary.
>>>
>>> Mark S.
>>>
>>>
>>>
>>> I have found that with my 66" dia =96 80" pitch prop my Velocity  =20=

>>> doesn't move until engine rpm is somewhere upward of 1500 rpm.
>>>
>>>
>>> I get about 5500 static with my 20B, and about 5600 on takeoff.   =20=

>>> With adjustable pitch you will want to get some higher numbers.
>>>
>>>
>>> Hope you find this helpful,
>>>
>>>
>>> Al
>>>
>>>
>>>
>>
>>
>> --=20
>> Homepage:  http://www.flyrotary.com/
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>>
>
>
> --
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