|
According to an on-line prop tip speed calculator at 70F,
you can spin the 76 " dia prop at 2550 rpm and have a tip speed of around mach
0.75 which still keeps it a bit on the low side of the desirable range for tip
speed (0.88 - 0.92Mach). However, there could be other reasons for the
restriction as has been mentionded such as structure limits, tip flutter, prop
track disc, etc.
Ed
Sent: Sunday, September 04, 2011 11:24 AM
Subject: [FlyRotary] Re: 20B Tuning
I think there must be a typo in the manual, I rechecked it this
morning and is reads 2150RPM. Instead of 2150 RPMs on the prop I am
thinking it should be 2550RPMs for a 76inch prop for a tip speed limit of 850fps
equating to 7250 engine RPMs. I will call the manufacture on Tuesday to
verify my calculations.
I appreciate everyone's comments.
On Sun, Sep 4, 2011 at 8:07 AM, Charlie England <ceengland@bellsouth.net>
wrote:
Wow. How big is it?
On 09/03/2011 10:50 PM, coastiefamily4 wrote:
Tip speed
On Sat, Sep 3, 2011 at 9:18 PM, Kelly Troyer <keltro@att.net> wrote:
Is the rpm limit because of diameter (tip speed) or a
structural blade limitation ?..............
Kelly Troyer
"DYKE DELTA JD2" (Eventually)
"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil
Manifold
"TURBONETICS"_TO4E50 Turbo
Sent: Saturday, September 3, 2011
6:06 PM
Subject:
[FlyRotary] Re: 20B Tuning
The prop is adjustable, it is hydraulically controlled. I
current have it set to the fine pitch setting.
On Sat, Sep 3, 2011 at 4:51 PM, Bobby J. Hughes <bhughes@qnsi.net> wrote:
If it's adjustable you may need more pitch. A 2150 rpm limit seem
very low. Bobby
Sent from my iPad
This is not full throttle, I have to stop at 6000 RPMs do to the
2150 RPM limit on my prop. I am using a VARI PROP, it is great so
far. I have plenty of throttle, just prop limited.
On Sat, Sep 3, 2011 at 3:44 PM, William Wilson <fluffysheap@gmail.com> wrote:
23.3
is just about exactly what would be expected.
Perhaps the
throttle is not opening all the way? You would have to have a
pretty convoluted intake to lose 3" of pressure in it.
On Sat, Sep 3, 2011 at 3:40 PM, <bktrub@aol.com> wrote:
At what density altitude was that measured? Maybe your MAP
needs to be calibrated.
Brian Trubee
|