Re: Re: Hints for Cat IV LPP flying
My method of incidence setup is at odds with what others consider normal. For high ceilings and lots of torque you're probably better off with the wing about parallel to the thrustline as Bob Bailey recommended. Whatever you wind up with for wing incidence always adjust the stab for optimum cruise. DON'T fly with anything other than an optimum incidence for the cruise part of the flight. I've seen many people who will change the adjustment to fix a power stall or "too much climb in a low ceiling" without readjusting the cruise. Most of your flight time is in the cruise and descent so make sure you've nailed that adjustment.
For motor weight probably the more the better until the gremlins start getting you. This will probably happen in the weight range you've already heard about. The gremlins are mainly associated with the motor length causing unresolvable tangles or the motor size causing launch torque issues or the extra flying weight causing structural problems like undesirable flexing. Lew Gitlow's book says that optimum for LPP is about 70% of model weight which is about 2.2 grams. I think you can go somewhat higher than this but I think 3 grams will probably be too much.
What works for you is going to depend on your model, your prop and how you set it all up.
----- Original Message -----
From: ykleetx
To: Indoor_Construction_at_yahoogroups.com
Sent: Friday, March 05, 2010 12:11 AM
Subject: [Indoor_Construction] Re: Hints for Cat IV LPP flying
Thank you, Bill, Mark, and Steve. I decided to follow Mark's advice and fly on a 1/5 motor. I launched with very little back-off between .6 and .8 in-oz, but I could not hit 30'. The best I could do was 20' with a time of 2:45. Steve's record is safe! When I "tossed" the plane to 25', the time was 3:05.
The plane climbs immediately at launch on the high torque, so I think my motorstick is stiff enough. (But .8 in-oz is A LOT of torque!) I'm going to adjust the stab's incidence to be inline or a little negative relative to the prop thrust. I think this should lengthen the climb. Right now, the stab's incidence is positive and probably reducing the climb.
I was also thinking about increasing the length of the rubber say from 2.5g to 3.0g. You guys have recommended 2.5g or less. Is 3.0g obviously the wrong way to go?
=Kang
--- In Indoor_Construction_at_yahoogroups.com, steven richman <topdawggt2006_at_...> wrote:
>
> First Hey Mark, Sorry I have not been around. Thanks for the shout out.
> Hopefully one of these days soon I will actually get back into flying. I do
> miss it greatly. I still have all my stuff, so hopefully its just like
> hopping back on a bicycle right?
>
> As far as CAT IV LPP. When I was making my run at the record, I did a lot
> of testing at USIC, using 1/5 motors. I think it is very beneficial, but
> expect times to be higher on your 1/4 motor testing, than actual times will
> be. This is mainly becuase the rubber wont bunch up and "distribute" the
> same as a full size motor, if that makes any sense. I also did not use
> sleeves on my record flights. Not sure if that would have helped or not.
>
> I belive my prop pitch was around 18, id have to do some searching. But it
> was a very high flaring prop. I think 2-2.5 grams of rubber is about right
> from my experince. I think my record flight was on .086-.088. Last comment
> is on launch torque. I launched at almost 1.1 In. Oz. With a flaring prop
> you will need much more torque to get it to the roof. I don't think .4 in
> oz. with any prop (unless pitch is very low) will get you anywhere near the
> roof. Hope that is somewhat helpful!
>
> -steven richman
>
>
> > For starters, I was wondering the approximate range of rubber size to use,
> especially to get to the ceiling. My prop is now set at 22" pitch. How does
> a 20" loop of .093" sound? Or does high ceiling flying require something
> like 24" of .080"? I plan on practicing using a 1/4 motor in the gym and
> later at Tustin to test.
> >
> On Wed, Mar 3, 2010 at 8:33 PM, ykleetx <ykleetx_at_...> wrote:
>
> >
> >
> > Thank you for the feedback. I'll start tonight with
> >
> > 1/4 motor of .60g will try .093" and .083"
> > ballast for full 2.5g motor -- plane weighs 5.6g at launch
> > prop pitch 18.5"
> >
> > And see how it goes.
> >
> > I'll ask about the motor sleeve later :-)
> >
> > -Kang
> >
> > p.s. I've been flying my daughter's 2010 SO plane. (competition is over.)
> > The best I could do is 3:45 at 30' no touch. Let's see how the LPP goes.
> >
> >
> > --- In Indoor_Construction_at_yahoogroups.com<Indoor_Construction%40yahoogroups.com>,
> > "Bill Gowen" <wdgowen_at_> wrote:
> > >
> > > I'm not a great LPP flyer in Cat 4 but I would guess you would do best
> > with something in the range of 2 1/4 to 2 1/2 grams of rubber in a motor
> > that is 20" to 22" long. You will probably need to use sleeves at both ends
> > of the motor. Your model should be able to handle a launch with something
> > over .4 in-oz of torque. You may need to use less pitch to get sufficient
> > climb but this will depend on your prop design and how much it flares.
> > >
> > > Maybe others will chime in with more or different info.
> > >
> > > ----- Original Message -----
> > > From: ykleetx
> > > To: Indoor_Construction_at_yahoogroups.com<Indoor_Construction%40yahoogroups.com>
> > > Sent: Wednesday, March 03, 2010 5:27 PM
> > > Subject: [Indoor_Construction] Hints for Cat IV LPP flying
> > >
> > >
> > >
> > > I have the opportunity to fly in Tustin in April, though I've never flown
> > indoor before, other than coach Science Olympiad. I plan to enter LPP.
> > >
> > > I would appreciate any pointers on how to fly in a CAT IV site like
> > Tustin. I now fly in a middle school gym where I can practice 30' no touch
> > flights.
> > >
> > > For starters, I was wondering the approximate range of rubber size to
> > use, especially to get to the ceiling. My prop is now set at 22" pitch. How
> > does a 20" loop of .093" sound? Or does high ceiling flying require
> > something like 24" of .080"? I plan on practicing using a 1/4 motor in the
> > gym and later at Tustin to test.
> > >
> > > Thank you.
> > >
> > > -Kang
> > >
> >
> >
> >
>
Received on Fri Mar 05 2010 - 11:08:15 CET
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