|Mar 12, 2013, 08:44 AM|
Do all delta wings need some uptrim?
Ok have made several post about this bird I found at a swap meet really cheap $40!! with Good retracts.
But It seems to be close to a Jet Centrys modle but not exsactly the same. There are a few othere older kits it seems to be close to but not exsactly the same, and I can't even find the info im looking for anyway.
So Im wateing for my 110mm edf fan to show up, and Im setting up the electronics right now.
So do all Delta wings need some intiall uptrim to fly properly?
Will HS 5645 Hite Servos be strong enof for the wings? They are a 168 oz digitals. I don't know what was in there before but its bigger than a standard servos so I guess 1/4 scale, but with its age, I don't think most 1/4scale servos were putting out a tone of power right?
The only info I can get on the throws is I need as much elevator as I can get, and use about 1/4 of that throw for airlion throws. Dose that sound right?
Im getting a max of 1 1/2 in up and down deflection on the elevator/ali.
So what would you use for a good low rate throws with this info?
Someone helped me with the CG wich is great!
Any info you guys can give me to prefent this bird from dieing would be great!
It will come in around 12 pounds with about 13.5 install thrust. with 12s 5000mah 40c lipos.
|Mar 12, 2013, 02:15 PM|
Yes it's a Delta Dart 106.
So how much reflux would you start with if you know nothing of the bird? I was thinking 2-3mm. Sound good?
I was thinking DX8. With 3 rates
High: full 1 1/2 ele and 3/4 Ali
Mid: 1in ele and 1/2in Ali
Low: 9/16 ele and 1/4 Ali.
These are my quess what you think?
|Mar 12, 2013, 03:43 PM|
Joined Aug 2009
The reason your plane requiers some up trim is because the thrust from your power system is in a line that lies above the location of the vertical CG. The thrust tends to drive the plane into the ground. On wings that use a prop, frequently the motor/prop are mounted much lower so the thrust line is closer to the vertical CG.
|Mar 13, 2013, 01:46 PM|
IWhy would you say High Wing Loading?
I can run this fan on 10s but I will have less than 1:1 power to weight ratio.
10s vs 12s is a diff of 320grams l wich is a little over 1/2 pound.
All I know is the wings are 42in wide the fuse if fiberglass and its about 71in long
|Mar 19, 2013, 12:16 AM|
A lot of RC models don't actually use flying wing airfoils. In fact, a lot of real world delta wings like the Mirage, the Eurofighter and the Delta Dart don't actually use reflexed flying wing airfoils so they use up trim too.
So to set reflex on your TX simply use the trim buttons. Or if you prefer the sub-trim menu. Or if you prefer adjust the length of your control rod (admittedly this last method this does not involve the TX at all).
|Mar 19, 2013, 02:07 AM|
|Mar 20, 2013, 11:40 AM|
You can find technical discussions by authoritative sources why a flying wing requires reflex (or why some do not require reflex). But when working on my very first flying wing about a year ago (Great Planes Phazer delta-wing EDF) it came to me naturally. Sometime near the end of assembly it occurred to me that without a horizontal stabilizer to “steer” or stabilize the wing, what was going to give it positive incidence to make it fly? After thinking about it for a few minutes I realized the elevons were going to have to be set with some up trim. “Up” elevon would push the trailing edge downward causing the leading edge to rotate upward (positive angle of attack?), thus allowing the wing to fly. Then I did a little research on the internet and my theory was confirmed – most flying wings require up trim (especially model airplanes which may not be using the absolutely best air foils for flying wings).
How much up trim for the Phazer? Who knows? I don’t remember how much I started with, but I erred on the side of caution and added more than I estimated would be necessary. Then, the plane would climb rather than dive simply requiring a decrease in up trim until I got it to fly level. This is how the maiden worked out and in the end the Phazer requires about 1/32” – 1/16” of up trim – not very much, but some for sure.
Since then I’ve worked on the Flyzone Hadron which also requires up trim as well as the Eraze which also requires up trim. In the case of the Hadron though, we anticipated the amount of trim required (through testing prototypes) and molded this into the fuselage body and the ailerons. Since this is built in I guess it would be called “reflex.” If the degree of reflex is not perfect the elevons will still require trim one way or the other.
Further thinking in my “own words,” I was also wondering why the lift of an airfoil alone wouldn’t be enough to make a wing fly? I’m guessing there must be many airfoils that could fly without a horizontal stabilizer, but the lift would probably be such that the wing might be too stable and therefore not suitable for aerobatic flight and/or inverted flight.
|Thread||Thread Starter||Forum||Replies||Last Post|
|Discussion Do all my ESC need to be the same for a quad?||kitetraveller||Multirotor Electronics||5||Mar 16, 2013 03:18 AM|
|Wanted Delta Wing plane, e.g wild wing used or new||littlephoenix||Aircraft - Electric - Airplanes (FS/W)||2||Jan 08, 2013 04:48 PM|
|Discussion Why Does My Plane Need So Much Uptrim?||krexken||Electric Plane Talk||18||Jun 30, 2012 04:35 PM|
|Discussion About to order some parts to cure mcx TBE...what all do I need?||crash331||Coaxial Helicopters||4||Apr 29, 2009 01:16 PM|