My first jet plane test pilots needed

[soulriver1]

Hi all so this is the first plane i made and i would like to know what mistakes you see i made how can i improve it what i should do batter in the future.Here are some question i have for you.

1.I put 2 oxidizer tanks in front of the plane to balance it if there any other way to move the weight more to the front so i don't have 2 useless tanks in the front?

2.Do you think it would be possible to get this plane in to space if redesign it a little?

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download link

http://www.speedyshare.com/W5rk6/Whitephoneix.craft

[Whatshtisthis]

This is only from what I see..

The CoM should be towards the front a little more since your plane is pretty large(it looks heavy, at least), you can adjust the fuel in the tanks to see the effect on the CoM as the fuel drains, the CoM might shift too far back as the fuel drains and render the plane unstable.

Remember, you can also move the CoL back if moving the CoM forward is too hard. You can also run some fuel lines from the front tanks you got to the fuel tanks the engines are using.

It should be able to reach orbit, attach some RAPIERs and try it out yourself.

Edited January 15, 2014 by Whatshtisthis

[Taki117]

soon as I load it up I will see how she flies, but I think it will just tumble backwards because of all the lift on the nose. Keep in Mind I use FAR so while it may not work for me, it might work in Stock.

[soulriver1]

Hey Taki117 dont know how it works in FAR but it flies normal in stock i would say it really stable.

[numerobis]

Did you fly it? How did it go?

My critique: you're letting function follow form. It's a pretty plane, but extremely wasteful.

For your first plane, I recommend a much, much simpler plane: one jet, one tank, a couple wings, a cockpit. Then build up as you need to add more. What you did build is huge. You didn't say what the intent of this huge plane is; as-is, it serves to fly a Kerbal around the world once while burning a lot of fuel. You have far more engines than you need for the mass you're hauling; if you had just two engines, you could fly your cockpit and fuel tanks vertically like a rocket and leave behind all the wings and structural bits. You have too few intakes to get up to very high altitudes, although there's enough rocket fuel to make up for it. Speaking of which, there's no rocket engines. Slap something on -- a pair of 48-7S, or a T30, or whatever.

[Taki117]

Did you fly it? How did it go?

It flies extremely well!

Javascript is disabled. View full album

However I would either widen the wheelbase or add outrigger wheels to the structural fuselages at the wing tips as they have a tendency to bend which results in the damage seen.

She has enough power to Ascend Dead Vertical. (Pitch 90*)

Max Altitude 21km (Stability issues after about 10km) Max speed >mach 1.5 (906m/s)

Edited January 15, 2014 by Taki117
Edit to fix album

[soulriver1]

Hi numerobis the intent for this plane was to make something that flies good and that it looks good yes i know most of things on the plane are wasteful and yes it can go around the world if you adjust fuel tanks and i had more intakes i remove so i get more fps when flying.So i build what i wanted it flies good and it a pretty plane i just wanted to hear what you guys have to say about it and to see what you would change about the plane so when i build my next plane it can be more efficient and also pretty.

Taki117 thank you for testing my plane as per your suggestions i dont have Far instal so it fly a lot different than u describe it dosent have Stability issues at 10km and the wings never brake on landing looks like FAR makes them weaker i will instal FAR and see how it change the plane.

[Taki117]

Far will change the Aerodynamics making rockets harder (Gone are the pancakes) but overall it improves spaceplanes. Also, the damage upon landing could have been due to my lack of piloting skill. (Also note that at 20,800km on descent I went into a flat spin/nose dive)

[soulriver1]

I just test my plane in FAR the wings are unstable vs stock where they are rock solid also in stock plane only goes to 14,000km when it runs out of air and never stall or go in to nose dive it seams to me that if u want FAR mod instal you have to start building it with FAR mod so you can test vs FAR mod Aerodynamics.

[Claw]

This thing looks gorgeous! I'm downloading it now and can't wait to check it out.

[Claw]

I was able to get up to about 22k and 1100ish m/s. Although the nose feels heavy and the pitch trim was working hard at the end. Your CoM is nearly in the center of your ship, which is actually pretty good, and you have a LOT of wing and engine mass behind your CoM. But your CoL is so far forward because you're using wing sections to create the forward hull. This is going to be a problem with this design and you might have to find something useful to use as ballast up front.

EDIT: By the way, I flew in stock Kerbal.

- I recommend more intakes. Four intakes for eight engines is not enough. I'm not saying you need to cover your jet with intakes. I find three per engine to usually be enough, but some people use a lot more. You should probably have at least one per engine though. You could slide a couple radials in between the wings or in that little pocket between the main body and the inboard wing engines. Remember, they don't have to be directly connected to your engines.

- I don't think you have enough pitch control. You have a lot of elevons on the wings, and they are what is causing your wings to flex so much during takeoff. However, they are closer to your CoM and aren't giving you nearly as much pitch as the tail.

- I locked the outboard most elevon on the top and bottom wing and the wings didn't flex nearly as much on takeoff. If you offload some of the pitch control from your wings, they won't flex as much and you might be able to delete some struts.

- Try adding some inline reaction wheels somewhere (maybe in the nose?). They may help your pitch trim keep up.

- You could consider adding a canard design and that would do wonders for your pitch, but I think this is a bad idea because it will shift your CoL forward a lot. However, depending on how you do it, it might also shift your CoM forward.

- Your CoL is sitting a little high compared to your CoM. I think for a ship this heavy and draggy, having a high CoL is causing what little pitch control you have to work extra hard. Try shifting the wing (or tail, because it's probably easier) down to lower your CoL and see how that works.

- Recess your cluster of four engines forward into the main body some. This will move the CoM forward.

- Your ship is so large, you actually don't need as much ballast as you have up front. You can fly it mostly neutrally stable (with the CoM and CoL in the same spot). Your ship has so much inertia that if you improve your pitch control, you will be able to hand fly and keep it from going out of control.

- Make a sandwich tail (similar to your wings) or add more tail area (with control surfaces).

- Replace the large control surface on the tail with 4 or 5 small control surfaces. This will boost your tail lift from 1.4 to 5.0, which will move your CoL back some and increase your pitch authority at the same time.

Anyway. I don't know if any of that will be helpful, but you have a beautiful ship and it flies pretty good below about 18,000 m. I tried adding intakes and messing with the tail a little and managed to get it up to 28,000 m at something like 1450 m/s. So I think you have a solid design that you can work off of.

Good luck!!

Edited January 16, 2014 by Claw