afpe45

there is no built in angle of attack in a tail less or flying wing hence the need for slight up elevon in design , the tail is what determins the angle of attack, in a plane with a tail and is built in in design,with the tail flat(with a spirit bubble on the tail) you will notice the wings have a slight posative angle of attack(usually) and you reduce or increase this by shimming the tail to avoid having to put in slight up or down elevtor in(drag) to achieve level flight at say just over half throttle or cruising speed,
if you wanted level flight at wide open throttle you would build in negative camberat the tail (angle of attack) when building the model(with spirit bubble on the tail the wings would have a slight downward attitude)
Someone will say I am wrong but that is what I was told in the instructions of my first model made by cambrian models(about 45 yrs ago).
afpe45.[8D]

and of cource all airfoil designs have lift at given speeds so the designers of the plane/wing have the camber built in for each diferent wing designs glide angle is calculated as well...and the ability to glide without stalling......it never ends....

Gryphon

iamman711,

I agree with Brazman, sure sounds like you are getting interference. I ignored that and paid the price......more than once (shhhhhh). [&o]

Try to move your receiver and antenna outside of the plane (hanging/uninstalled, but taped down) for test purposes and see if the unwanted jitter stops. May want to try it outside of your room. Tap the antenna down too. Test with motor on and off, ask for help from a friend.

I'm guessing that you have 72 MHZ radio... That is the only time I had unwanted servo twitch. Buzzing sound is o.k. but movement you can see is not o.k....not at all. Do not even risk a flight that way...I got taught that lesson more than once....too hard headed at times.

Buzzing with servo arm removed is not a good sign, especially that you saw movement...that very possibly can be interference. A buzzing that you can tap the stick once and is gone and stays gone with servo arm connected to moving surface is o.k. if there is no unwanted movement. Any movement is a NO NO….even a single kick.

If 72 MHZ, then you need to try to install your receiver in front of battery or far away from motor and ESC out on the wing (if not in front of the battery).

If 2.4 GHz, then I would try to do some part swapping with your other parts on hand to see what you can find...almost willing to bet that it is not 2.4 GHz radio....almost.

BubbleGum had same issue, and since he didn't want to have the battery smash the receiver in a crash (same view as me), instead of putting it on top of wing as the rest of the guys had to, he placed it under the front of wing (not sure which side) because he has landing gear.

You also have landing gear....either dig up his pic with receiver location in part 6 or send him a PM and ask him for one. He is a very cool guy and would not mind giving you a pic.


Let us know what you find. Just start with moving the receiver and antenna far from ESC/and motor and tape it down on front of wing and see if the issue goes away.


Guaranteed crash if you ignore it....I have more than 2 bags of saved parts from Stryker crashes (that is all I will admit to tonight).... I will take picture if you ask me to....LOL...back then I didn't find it so funny.


Good luck,

Gryphon

iamman711

Hey Brazman,

I have the dx6i by Spektrum. I have the AR6200 Rx. Before I replaced the servos, there wasn't this issue. I hear the sound when I travel from one end of the servos' travel to the other,

Hey Gryphon, I don't know what to do. 2.4 Ghz. This issue didn't happen with stock servos. The youtube video is poor quality, but I get the buzz sound during control movement of the servos as well as if i hold the servos in one end position (left/right for aileron, up down for elevator). also, sporadic jitter without control input.


Edit: when i removed the servos, along with the receiver and operated the servos same issue, so i dont think its the radio that is to blame. should i assume i have stripped servos?

WESCAM

My journy to the dark side is almost complete. I have started to fit everything inside plane. My mega 16-25-2, CC 80 amper, and T.P. 4s 3850mah 25C should be installed by the end of the weekend. I will try to post pictures if I can get my daughter to help me (her camera) with that. Epoxy will be nice in dry that i used on the 3 straps that I used to hold battery in by morning.

chippedprop

Stryker is changing before your eyes

I've been working on the stryker
pic-1 shows what I used to line the sides of the now enlarged bay-this is a proven method from cadetman from thread 2 to add side and front to back reinforcement in the bay area
pic-4 shows the new width
pic-5 shows the before width

I used a thin coat of high temp glue stick to stick it ( burnt my fingers but it works) CA can/may fracture as the foam bends over the long distance hot glue will flex with it

chippedprop

Ok now let's start up the saw and start cutting foam
pic -1 removed the trailing end pieces for the stabs. and transferred the hinge line to the center point of the fuse
pic-2 bottom view-I removed the remaining foam with my trusty fine tooth hack saw blade-lay it on the foam and follow the foam-saw slowly with light pressure-don't rush
pic-3 down to 6 ozs
pic 4 and 5 my home made foam cutter-mark a line -follow the line and... TA-DA- I ALWAYS cut from the bottom- why- it's flat and will automatically transfer a 90 deg angle to the edge you just cut ... like say for adding trailing edge stock..which will be later
pic 6 hack saw blade to finish the cut-follow the line
pic 7 a little sanding will be required to make sure the new edge is straightman look at that !!!

The amount removed is from the stock hinge dimple to the stock trailing edge
The balsa stock I will add will be less then the amount removedthe balsa elevon will be the same size as stock elevons which makes the over all wings width shorter or less then stock = less wing area less dragand yes less lift

Flightops_69

Thank you for the pics and steps you took Chipped, I only have one question. On your last pic, of your last post, your showing what looks like a well made and well formed T.E. that seems will form into the rear of your acft. I was wondering how you made the T.E. My T.E. is just 2 single pieces of squared balsa wood glued to the rear of the stryker. Yours looks like a machined single piece (to me).

Gryphon

Flightops_69,

I think that is just the foam that he cutoff.

Flightops_69

Ahhhh, thx Gryph <sheepish grin>

chippedprop

Flightops_69

Yes it is just the removed foam-but the balsa I will add will be 3 pieces jointed to make 1 I hopethis is a new idea I have so we'll see how it works outor not
The goal is to ....
1-have stronger motor deck so you have zero foam flex = loss of power to propand straight line thrustwhich I have done with the other planes
2-able to switch motors quickly...so you want to race..give me 3 minutesinrunner or outrunner
3-stronger trailing edge then foamI know basswood IS stronger but weighs more
4-able to run a 7-8-9 inch prop without having to trim vert. stabs.
5-and of course better performing plane = much biggger smile !!!!!!!!


Gryphon

remember the flat CF I bought ??? Guess how I'm going to use it.

CP

Yes this takes a little work - which I like

Gryphon

So guys...any big plans for the weekend? Any maidens? and experiments or OVER propping? [sm=bananahead.gif]


Chippedprop, I know I never got my T.E. at a perfect 90 degree. I'm very impressed. You do good work...very good work.



Gryphon

chippedprop

Simple works and most of the time I get LUCKY

Spid

Wow! Tough question. Lots of variables to consider....

It is not true that mass has no effect on the top speed of an aircraft. But mass itself isn't slowing down the top speed of the aircraft. The drag created by the increased lift requirements is slowing down the aircraft. So directly i say No, but indirectly, Yes to a degree.

In theory, mass does not effect top speed in level flight since the weight is perpendicular to the drag vector and thus has no horizontal component but there is really no cut and dry answer because the heavier the airplane, the more lift is required to counter gravity. The more lift required, the more turbulance of the air you generate and that equates to more drag.

But with the fast darkside stuff we fly and the thrust/power these things produce, wieght/mass it really isn't a major component to consider (IMHO). However, I will say that in my experience, a lighter plane flies better (all other things being equal).

Thanks,
Kevin

Gryphon

Hi all,

I just got a PM saying that Randy at Dynamo Electrics has closed shop. Sounds about right to me. I've been trying to send him some business for a while now and he has been MIA.

I was also told that the last of his stuff was sold at huge discounts. So lots of specifics there.

I hope he is doing O.K., I remember he had some back problems....He is a good guy and I wish him well. Took good care of me.

His web site www.dynamoelectrics.com has not worked on my computer and his phone is not getting answered.


If you guys know better, please let me know.



Gryphon

Gryphon

Spid,

Thanks for the reply.

You said: "However, I will say that in my experience, a lighter plane flies better (all other things being equal). " I 100% agree with you at lower flight speeds.

But at high speeds, the heavier plane is so much more stable, especially when there is wind.


Just like you said there are lots of factors involved and no doubt if a person goes to a small field and wants to just have fun flying the Stryker slow in the park, he is 100% better off in almost all category with a light plane.

My views and I may be wrong:

As far as max speed goes, if we are taking about such a small difference that hardly accounts for anything, then making a comment that a heavier plane will fly slower will unduly give the wrong impression to people.

They will think: “NO!!!! if I add weight, I'm going to lose speed.”

So conceptual stuff aside, practical applications should be considered and the forum and the readers.

Lift is from speed not weight given a fixed airframe. So the extra drag is from increased speed for all practical purposes. Now if we were designing for minimum speed then that would be a different speed, then for extra weight higher speed would be needed and because of that we would have higher turbulence, drag, etc...

At our 100+ MPH high speeds, we are encountering too much lift already {especially above 115MPH it starts to get worse exponentially it seems like as the we go faster and faster}


Gryphon

Flightops_69

There are four forces acting on an
airplane in flight: lift, weight, thrust
and drag.
Lift comes from the wings. What about
the other forces?
Weight is a force caused by gravity,
directly opposite to the lift force that is
pulling the airplane up. For level flight,
lift and weight must balance each
other out.
Thrust, caused by the airplane's
engines, is the force that moves the air-
plane forward. If an airplane did not keep
moving, air would stop moving over and
under the wings. Without this movement
of air, the wings could not create lift, and
the airplane would start to fall back to the
ground.
Drag is the force that tries to slow
down a moving object. To lessen the drag
on an airplane, most airplanes are made
more aerodynamic, or streamlined. Just
like lift and weight are opposite forces,
thrust and drag are opposites to each
other too. For an airplane to keep flying,
its thrust must be bigger than its drag

Ok, 4 different forces. Any change in one can be changed to a degree by the other, until, you surpass the individual flight characteristics of the airframe. Thats why each airframe has published data, and what to do put on the emergency checklist depending on airspeed, altitude, fuel, weight, ect.... We are flying an R/C foam plane that has no published data (as far as I'm aware) and we experiment to find the best results in a particular area. (in our case - speed) I guess, in a nutshell, its all trial and error. If we understand the forces in play we can make allowances in those various factors whenever we make a particular change to the stryker.

Gryphon

Flightops_69,

Just get ready for your afterburners. Either Medusa or MEGA......the DARK SIDE has its eyes on you....trust me, I feel it..................................MUHAHAHAHAHAHA . [8D]

Maybe next year......after Co-pilot for total relaxation and peace of mind.


Gryphon

Spid

It's all good Gryphon. My bad for some mis-interpretation on the above post. Thanks for taking the time to PM and explain things. I probably should have done the same.

Your friend,
Kevin

Gryphon

Spid,

I'll PM you.

I feel horrible that my post made you feel bad. Spid just remember our past interactions and please know that there is a misunderstanding.
_________________________

Edit: Thank you for your awesome reply PM.........hmmmmmm, does that mean I can still get Doppler readings from you.......LOL.........



p.s. Back then, I had called just called up chippedprop about a question, I then clicked on refresh button, then my heart missed a beat. I kept saying ummm, ummm, ummm, chippedprop was like: "what are you saying?".
I better wipe the tears of joy right now...Later.


Your long time friend,

Gryphon

Flightops_69

The copilot is my next purchase, probablly mid-month pay. Now, when I get back from Thailand/Singapore for my ATC visit, I'll have that extra TDY money for the Medusa and battery upgrade. I'll have to go back to part 6 and re-read alot of stuff. My fuzzy area is the BEC. JUST found out what that is, I'm not sure if I need that <thought the ESC took care of that function>. Think I'll turn my current bird (the one I posted pics of) into a dogfighter for field fighting with the local guys, and get a new body for speed. I've got enough parts now for 2 flying birds.

Gryphon

Have a fantastic weekend everyone.



Gryphon

Brazman

This is all true...although!! If for example the airfoil of a 50oz plane is generating 50oz of lift at top speed at 0deg AoA then there is no extra drag created. If the plane weighed 60oz at the same speed it would need a positive AoA to remain level and would therefor be slower due to more drag. If however that plane weighed 40oz at the same speed then it will need a negative AoA to remain in level flight which will create drag as well. We need a wind tunnel dammit!!

Stryker_Viking

WOW,
I am so sorry to have caused all this guys, my bad as I should have taken the time to quote what I was responding to so to avoid the risk of being taken out of context.
Here is the complete “version” of what I attempted to respond to…

AND

Above questions was sloppy replied to with:


THIS RESPONSE WAS BASED ON THE MEGA 16/15/ SERIES COMPARED TO MEDUSA 028-040- SERIES, TWO DIFFERENT SIZED MOTORS...

Sorry guys...

Have a great weekend
Stryker_Viking

Spid

I follow you Brazman. I think in general you'll find that weight has some, but very very little effect on top level speed, since the AoA is near zero or at zero and the coefficient of drag is probably at it's minimum or pretty darn close to it. Increasing the mass/weight will increase the AoA but by such a small degree or fractions of a degree that it will have a very small effect on the coefficient of drag which in turn will then have a very small or neglabile effect on top speed.

With high speed planes it really centers around drag on the airframe. What can we do to reduce drag to be able to increase speed. (sleeker airframes, rounded leading edges, tapered trailing edges, thinner airfoils, etc..., all that good stuff). As flightops posted, there are several variables to consider and they all interact on one another to some degree.

In our applications here I really believe that any impact an increase in weight/mass has on top speed is so small that it is negligible for all intensive purposes.

So right or wrong, here is where I stand on the whole weight/top speed discussion:
In Theory - Directly: No Indirectly: Yes to the degree it effects the other variables on a given airframe (coefficient of Drag, etc...)
In Our Applications: No (or to a point to where any effect is so miniscule it is not noticible or can not even be measured)

I always wanted to build a wind tunnel for RC planes. I think that would be very cool. Maybe someday after I retire in 23 years if I'm still around...

Great discussion!

Brazman

Just finished filling the bottom of my stryker after installing the lateral spar and the ply laminate on the mount area. Hopefully I will get the top done today too and maybe glass it tonight. Will be pushing it though. I will try to post some pictures later