RC-Captain

To calm every one's NADS, the plane is tail heavy, and very uncontrollable. I have to repair the wing and then this weekend I will move the battery forward toward the CG.

As far the way you guys find the CG to each his own . I understand you guys move the wing to balance the plane but someone like me might like the position of the wing and would just shift the equipment around to balance the plane instead.

I'm currently building a DDUST , go look for the thread : THEN THERE WAS DUST : I'm stuck in how and where to secure the tank which is 8oz.

PS I'm hard headed but I really like to learn.

Muldoer

Why go simple and get it flying NOW versus keep doing this complicated and keep struggling to get it flying at all.

jessiej

I am really trying to help, FIEND, but you make helping distasteful task. Being hard headed however, I shall persevere.

1. Based upon your first paragraph, you knew the plane was tail heavy. I am somewhat mystified why you chose to try to fly it without correction, except for your second paragraph which indicates that you liked the way it looked and chose to fly it in that configuration regardless of the laws of aerodynamics.

2. As for "finding the center of gravity", there is no mystery there, no esoteric formula. Perhaps you could better explain why you have difficulty with the concept? I assume that with the craft in question you have a basically rectangular planform so Mean Aerodynamic Chord (MAC) should be a no brainier. Perhaps it might help you conceptually if instead if thinking of "center of gravity", you thought of "Balance point". Measure the chord (leading, as in "front" edge to trailing "Back" edge of the wing. Divide that measurement by 4. An inexpensive calculator will do this calculation easily. The answer will be a good starting point to determine where your SPAD should hang level if you pick it up with your fingers under the wing tips that distance behind the leading (front) edge of the wing. I strongly recommend that you perform this exercise BEFORE again attempting to fly. And remember, the S in SPAD is for "Simple". Keep it that way and you will simplify your effort and you will enjoy success.

3. Your only statement with which I would take issue is: "I really like to learn".

Good luck, and keep us posted on your progress.

jess

RC-Captain

The reason I don't like the moving of the wing bit is because I asked in the aerodynamics room , 'how to find the CG and a moderator gave me a program and it worked. No one is going to fly a plane with the wing that looks completely out of place at least I won't . I want it to look like a plane first then everything else comes into the equation.

For you the wing sliding works , and I don't know why you persist with trying to make me see things your way with this method. To me it doesn't make sense. I'll try to explain a little better . Although a SPAD plane is not a balsa plane I fail to see and difference in obtaining aerodynamics. You have a wing and two stabs horizontal and vertical. Outside of that what the plane is made of is the only difference I can see. Not to mention, how do you know where to but the points of the CG machine without using a program to tell you how many inches from the LE the points should go. Yes I know the spar is the normal location but what if you use to spars ?

No I'm not trying to make it hard or trying to ignore the information given to me, but I want to understand fully how I will make this plane fly and if I crash a few time then so be it no sweat , I rebuild and keep at it until I get it right.

Having said that thanks for your help and ideas, and I will definitely let all of the SPAD fliers on this site know when I have successfully flown a SPAD plane.

PS not to give you a headache but my DDUST is coming along fine. I'm going with an 8oz tank so already I changed something but I think I will make out alright.

jessiej

[quote]ORIGINAL: RC-FIEND

[The reason I don't like the moving of the wing bit is because I asked in the aerodynamics room , 'how to find the CG and a moderator gave me a program and it worked.]


Evidently not. Your plane crashed.


[ No one is going to fly a plane with the wing that looks completely out of place at least I won't . I want it to look like a plane first then everything else comes into the equation. ]

Feind, you should remember that form follows function. If your fuselage is so out of balance that the wing has to be placed in an extreme location you obviously need to reposition gear


[For you the wing sliding works , and I don't know why you persist with trying to make me see things your way with this method. To me it doesn't make sense. I'll try to explain a little better . Although a SPAD plane is not a balsa plane I fail to see and difference in obtaining aerodynamics. You have a wing and two stabs horizontal and vertical. Outside of that what the plane is made of is the only difference I can see.]


You are correct so far. The basic principles of aerodynamics have not changed since I majored in aerospace engineering and apply to craft made of any material. The difference in (most ) balsa designs and SPAD planes is that with the SPAD you CAN move the wing. This principle has been explained in previous posts.


[Not to mention, how do you know where to but the points of the CG machine without using a program to tell you how many inches from the LE the points should go. Yes I know the spar is the normal location but what if you use to spars ?]


You do not need either a machine (use your finger tips) or a program (use a ruler). A good rule of thumb to place the CG is at 25% of the wing chord. Example: The chord is 12". 25% of 12" is 3". Therefore balance the plane 3" back from the leading (front) edge of the wing. Note that I did not mention spar location. Placement of the spar(s) is a structural, not aerodynamic consideration. You are using a rectangular planform, so the calculation for CG is simple. (Note once the plane has flown you may wish to adjust the CG, more tail heavy=more sensitive. for initial flights it is better to err on the nose heavy side. This too has been pointed out in previous posts in this thread.


[No I'm not trying to make it hard or trying to ignore the information given to me, but I want to understand fully how I will make this plane fly]

Should you fail to understand any of the above let me know. Note that we have addressed only CG. I am assuming that the tail surfaces are properly proportioned. I further assume that incidence, decalage and thrust line are reasonably correct and that you have a workable airfoil. You are after all, working with a very simple, basic design and not that much can go wrong. My only further recomendation is that you behave in a civil manner with those who take the time to try and assist you.

jess

ChrisSpad

jessiej,

i went through this same thing with balance with RC-Fiend several months ago. Its kind of amusing to read:
http://www.rcuniverse.com/forum/m_26...tm.htm#2654155

RC-Captain

How am I not acting civil toward you ? I didn;t curse, use caps, or tell you to beat it. I guess you read chrisspads link [sm=lol.gif]. Dude I'm human just like you . I have a personality just like you , I have bad and good days just like you , beleive me I come across the ugliest , nastiest people in the world and I know how to react in a civil manner . I have never been incarcerated, been arrested, or even been fired from any of the 50 jobs I have held since I began working when I was 15. So pleasedon't say I am not civil because I am very far from that. Besides no one owns me , so telling me how to act is a waste of time.

If you Jessie have aerospace training I should be able to give you the measurements of the wing and stab and the weight of the equipment and you should be able to come up with the CG. So thanks but this has already been blown out of proportion . You have a habit of preaching instead of teaching. Thanks again

jessiej

So much for the civility huh? Evidently you do not read your own posts. (Can't say I blame you) I am sure that maturity is WAY to much to ask from you .

BTW I have no idea what you mean about "chrisspadads link" Some one else who thinks you are an *****? Again you are certainly not "Just like me." And I Would deny to my dying breath that Your personality is "just like mine". I am pleased (though somewhat surprised ) that you have not been incarcerated. I must say that I am a bit puzzled that you would feel that you needed to state that you had not been jailed. A most unusual statement.
Do you think others on these fora feel you have been/should have been imprisoned?

Question: If you have had 50 jobs in the (presumably short) time since you were 15 why can you not get a good job and keep it? I expect that those who follow your posts know the answer to this question, but your explanation would be, umm, should we say, interesting?

Indeed, if you give me the measurements etc. that you speak of I could give you the CG, but others have also done so and you have ignored their advice and in doing so have failed in your attempt to fly your, um, "design" I would therefore encourage you to continue with your scientifically advanced SPAD, Powered By your 18000 RPM engine (doubtless powered by your windshield wiper fluid fuel and mega volt plug, lubricated by "petroleum distillates. In so doing you will undoubtedly surpass the best efforts of any modeler since 1940 or so.

Still amused, but still willing to help. Some never give up

jess

kracker

Hang in there. Look over your plane and make sure it is to the plan. If built to the plan and balanced to the plan, it should fly great. Drilling the holes in it should not change the way you check the center of gravity. It will change the distance recommended in the drawings though. Just make sure it balances on the spar where the prints show. The 4mil on the bottom and 2 mil on the top is a great wing. Good luck and keep trying. I have built several spads and they have all flown great.

jessiej

That has been the experience almost all who have tried them. Some , however can evidently find a way to screw up the internal workings of a ball bearing.

jess

RC-Captain

Dude let me tell you something , It may seem obvious to you that I am in here to clown around but I'm not !

I don't mind your suggestions but your snide remarks are killing me and my progress in this hobby. There are many people in here that think I am an ***** but I can care less. None of them helped me in the beginning and I would bet my last hard earned dollar none of them will help me in the end. Above and beyond I come here to obtain suggestions not life lessons . I have a FATHER who thank GOD is still alive that can give me advice on life lessons . I am 35 but a kid at heart do to the Jones I have for flying these toys . But as far as out side of this hobby thing I pay my own bills , I work and I depend on nobody but myself. So make sure you have your misconstrued information together before you come off like you are the best thing that happened to RC period.

RC-Captain

Did you ever post anything about having a crash ? i'm willing to bet you have crashed but never posted it because you think you are GOD's creation to RC. I thought I could stay calm with your negative remarks but you have pushed my last button with this pompous nonsense. This is a forum for people trying to get help . Not a forum for following BIG BAD NO MISTAKE MAKING I KNOW EVERYTHING JESSIE. I just have to say you have no class at all . Absolutely the bottom of the barrel class. Find a personality and stick with it you may start to love yourself.

jessiej

You got that right.

jess

RC-Captain

[X(][sm=spinnyeyes.gif]

jessiej

Definite signs of improvement,FIEND. Congratulations on the good work! Your last post, quoted in full above, makes far more sense than the previous ones, Keep striving for improvement!

jess