RE: NEW KMP 95" B-25  
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RE: NEW KMP 95" B-25 - 6/23/2008 10:53:52 PM   
derrickxp8103


 

Posts: 10
Joined: 9/4/2005
From: Carencro, LA, USA
Status: offline 		I wonder if two YS 63's would fly the B-25 ?

(in reply to echavi9325)
       Post #: 51

RE: NEW KMP 95" B-25 - 6/23/2008 11:11:46 PM   
alanc


 

Posts: 643
Joined: 12/15/2003
From: manchester, AE, UNITED KINGDOM
Status: offline 		put simply, no


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ALAN, UK sales and promotions, YT INTERNATIONAL,

(in reply to derrickxp8103)
       Post #: 52

RE: NEW KMP 95" B-25 - 6/23/2008 11:22:52 PM   
Rip n Bank


 

Posts: 503
Joined: 3/12/2005
From: Fort Collins, CO, USA
Status: offline
quote:

ORIGINAL: derrickxp8103

I wonder if two YS 63's would fly the B-25 ?


Big question is: will ONE of the YS 63's fly the KMP B-25!!!

WHEN one of your two engines quits (gonna happen), AND if you're already above "minimum critical airspeed" (MCA), then you'd want your single remaining engine to continue to overcome drag and keep the aircraft above MCA until you can make an approach. I would guess a single YS 63 could not do that. Perhaps they'd work fine with a TF B-25, but this plane is significantly larger (cross-section = drag), and heavier, than the TF.

Of course, if your remaining engine can't sustain an airspeed above MCA, or if you're under MCA when you loose any engine, then you'd treat it as a deadstick and "establish a glide slope" because you're going to "land", whether there's a runway involved, or not!

Rip

_____________________________

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(in reply to derrickxp8103)
       Post #: 53

RE: NEW KMP 95" B-25 - 6/24/2008 12:44:19 AM   
kahloq



Posts: 1797
Joined: 1/1/2006
From: Fort Collins, CO, USA
Status: offline 		2 YS 63's would work fine for the H9 B-25 and even the earlier version of the KMP 85" one, but like ALan and Rip stated, not for the 95" KMP. It would be marginal on the TF B-25.

Even on the 85" KMP, it would be kinda iffy. Im putting two saito 91's in the 85" KMP version. A YS 63 is about the same power output as a saito 72 I believe. I orginally considered using the saito 72's and actually bought a 2nd one to do it then thought about more and opted to use larger .91 motors. Mostly because of the MCA Rip mentioned, but also because they can spin a lot larger prop then a saito 72 can.

(in reply to Rip n Bank)
       Post #: 54

RE: NEW KMP 95" B-25 - 6/24/2008 2:13:25 AM   
AKondor


 

Posts: 384
Joined: 10/11/2002
From: Thunder Bay, ON,
Status: offline 		HI:

I would go with .91's Of course the RCV 90SP would swing some nice scale props and fit with no holes to cut in the cowl.
Just my 2-cents

_____________________________

Andrew Kondor
KMP Models

(in reply to kahloq)
       Post #: 55

RE: NEW KMP 95" B-25 - 6/25/2008 2:03:47 AM   
PA757


 

Posts: 177
Joined: 6/9/2008
From: St Cloud, FL, USA
Status: offline 		Well,

After talking to Steve at Bob's. I'm sticking with the Saito 100 instead of converting it to RCV 120's. I went to buy the cowls for the RCV and ended up buying another B25 for parts! Just in case I want to change the engines again, and of course, bang it up! If I have any part's left over will sell them to anyone who needs them!

I wanted to keep it as clean as possible but the Saito 100's stick out and the muffler exhaust port is right at the cowl radius.

Having a blast with this build! Looks Great!

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(in reply to AKondor)
       Post #: 56

RE: NEW KMP 95" B-25 - 6/25/2008 6:24:16 AM   
eldher13


 

Posts: 14
Joined: 1/25/2007
From: Fort Collins, CO, USA
Status: offline 		I'd just like to clean up our terminology a bit, Rip. Your theory is right on, but let's keep the acronyms correct.

There is no "minimum critical airspeed". It is just "critical airspeed" required for twins to maintain stable flight with one engine. Minimum would imply some range or similar concept, and there is none.

MCA is, however, an aeronautical acronym for "Minimum Contollable Airspeed" and is an airspeed just above stall. Pilots practice flying at MCA to become familiar with the behavior and feel of the plane just before the stall. The goal, likely obvious, is to help _avoid_ a stall by being acqainted with the feel before the stall occurs and thus the pilot can take corrective action. MCA flight is also used to help the pilot learn fine control of the aircraft. The pilot will need to maintain staight and level flight as well as turn at MCA _without_ inducing a stall or loosing altitude. You learn a fine touch on the yoke and throttle doing this. MCA is set up with the airplane in both dirty and clean configurations.

(in reply to PA757)
       Post #: 57

RE: NEW KMP 95" B-25 - 6/26/2008 1:45:32 AM   
PA757


 

Posts: 177
Joined: 6/9/2008
From: St Cloud, FL, USA
Status: offline 		Sweet!

Here is my Amateur Build! Wanta Paint Mine?

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       Post #: 58

RE: NEW KMP 95" B-25 - 6/26/2008 2:55:54 AM   
PA757


 

Posts: 177
Joined: 6/9/2008
From: St Cloud, FL, USA
Status: offline 		I moved my GT Mustang out of the Garage for the B25!

Benefits of being Divorced and having a Girlfriend in South America!

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       Post #: 59

RE: NEW KMP 95" B-25 - 6/26/2008 3:01:52 AM   
PA757


 

Posts: 177
Joined: 6/9/2008
From: St Cloud, FL, USA
Status: offline 		Here's Week 5 or so.....

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       Post #: 60

RE: NEW KMP 95" B-25 - 6/26/2008 3:03:30 AM   
PA757


 

Posts: 177
Joined: 6/9/2008
From: St Cloud, FL, USA
Status: offline 		...

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       Post #: 61

RE: NEW KMP 95" B-25 - 6/26/2008 5:34:36 AM   
eldher13


 

Posts: 14
Joined: 1/25/2007
From: Fort Collins, CO, USA
Status: offline 		All,

Well, I will have to eat my own MCA

Doing some additional research, MCA is used for both Minimum Controllable Airspeed and Minimum Critical Airspeed. The latter is a defined 'V' speed, refered to as Vmc or sometimes Vmca (also called Mimimum Single Engine Control Speed). It is definied as below. Anyone interested in details about this, please see these web sites. NOTE: Vmca can CHANGE with increased bank angles!!! This has real ramificaitons for us twin pilots. See the accident report link.

Definition
Accident
Mulit Engine Instructor Quick Refernece


Short Definition
Vmca, the minimum airspeed at which an airborne multiengine airplane is controllable with an inoperative engine under a standard set of conditions, is arguably the most important piece of aeronautical knowledge a multiengine pilot must understand. Unfortunately, most of the texts that are commonly available treat this subject inadequately. The purpose of this discussion is to provide thoughtful insight on the conditions under which Vmca is determined and how they affect the airspeed known as Vmca.

When a manufacturer of a light multiengine airplane certifies that aircraft, one of the limitations that must be established as a condition of certification is Vmca. Every manufacturer is bound to the same set of criteria when determining this limitation. Those conditions are (in no particular order):

Critical engine at idle power setting.
Critical propeller windmilling.
Operating engine producing maximum thrust.
Landing gear up (normally).
Flaps up (normally).
Aircraft loaded at the most aft allowable center of gravity.
Aircraft loaded to the maximum gross weight.
Up to five degrees of bank toward the operating engine.
Atmospheric conditions normalized to standard day at sea level pressure.

With these conditions observed, airspeed is decreased until heading cannot be maintained. That airspeed is noted, and subsequently marked by a red radial on the airspeed indicators of the production models.

(in reply to PA757)
       Post #: 62

RE: NEW KMP 95" B-25 - 6/26/2008 5:48:29 AM   
eldher13


 

Posts: 14
Joined: 1/25/2007
From: Fort Collins, CO, USA
Status: offline 		Oh, I should have added a link on the Minimum Contollable Airspeed, which is relevant to planes with any number of engines (0 or more).

Minimum Controllable Airspeed

(in reply to eldher13)
       Post #: 63

RE: NEW KMP 95" B-25 - 6/26/2008 6:13:48 AM