JohnBuckner

My Feedback: (1)

OK Robby fair enough question. First off Let me say that one of the minor goals with this thing was to try to acheive the best engine out performance (read controlability) without resorting to artificial means (read gyro/money).

With both of my prior forty size trainer twin bashes with .20's by using somewhat more than normal out thrust on both sides, as much as five or six degrees to minimise yaw not of course eliminate it. The disymetry of thrust form an engine out causes a yaw and not a roll (the roll is a couple result of the yaw) The out thrust is very effective limiting the yaw, something that has been used for many years in most propellor driven twins but not so much on RC multi's, Why? At any rate my little twins were very effective one one engine and the second one was capable of single engine take off that I had demonstrated a few times even on very low power.

Where is this going? you might say and what does that have to do with having more power? Well when you have an aircraft with more powerful engines the sudden loss of one engine will result in a much higher percentage of thrust disymetry upon that loss which greatly diminishes that controlability that we were trying to acheive in the first place. This is not to say having a high power to weight ratio multi is not a good idea. Most RC multi's are so, But then agine the most common advice given to multi RC pilots is to shut off the other engine when one is lost and I just would rather make the effort to have a controlable airplane that could operate safely with an engine out. At some point I intend to test it with two out on oneside And I do think it is possible although probably not at full power and most likely in a descent (something the FAA likes to call drift down) but still under control and of course extending your options on where you can land.

Well thats my story and I am sticking with it. Oh yes, concerning the sound of the little engines, I, would be willing to bet you have not seen to many stick built quads and as we all know stick built airplanes make an entirely differant sound in flight from airplanes with a higher structural density. The sound is not only unique but awesome

Robby, to the only guy in the world who spent the time to hand polish a couple of LA-40's to the most increditable mirror finish. All I can say is, Hey man when you gonna do mine

John

Robby

My Feedback: (18)

John, very good analysis.. As you remember the little white Twin
Stix, that little baby has excessive out thrust as seen in the pics
where I 'drew in' a line for reference.. Even with as much o/t as
it has, drop an engine and it becomes totally out of control. WHY ?
Simple answer.. Take plane that is suppose to have .25's and
drop .40's on it... Plus that plane is over weight creating the
need to keep airspeed up so plane doesn't fall out of sky...
By extending the leading edge of on both sides it has REDUCED frontal drag, reduced tip stall, and reduced wing loading..
I haven't tryed an engine out since the wing mod, but booyyyy ohhh boyy, it does handle a TON better.. I can even land it like a normal plane now instead of coming in like a jet..

Now about that little polishin' job you have.... Hhmm, I do
have a new wheel coming next week I am anxious to try out..

William Robison

My Feedback: (3)

Robby and John:

Since I have been invited to comment -
This is the basic difference between the considerations for passenger carrying planes and "UAV's" and planes remotely flown for pleasure with local radio control. When the airplane is a tool we want to keep going regardless of mehanical casualty, as a toy we can cut power and land at any time with no loss. Unless we had a side bet going.
The lowered VMC is important to the FAA, and to you when you're inside. From the outside it's not so important. Haw.
I have done this with no offset, though admittedly with the left engine. Haven't tried it with right engine only.
Not so, John. 25% is 25%. But with higher power and the same airframe weight it may seem like more.
Well thats my story and I am sticking with it too. John is designing from the standpoint of continuing after a mechanical casualty, I go for maximum performance with all engines turning and burning. In this case you make your choice before paying your money.
John and I are in total agreement here. Question, though. Why LA's, and not engines? Haw.

Bill.