Go Back   Knife Edge > RealFlight - Designer's Corner > RealFlight G3 - Designer's Corner
Use of this site is subject to our Terms of Use. | Looking for technical support? Read this!

Reply
 
Thread Tools Rate Thread Display Modes
  #1  
Old 07-20-2007, 01:29 AM
RocketFlyer's Avatar
RocketFlyer RocketFlyer is offline
Registered User
 
Join Date: Mar 2007
Posts: 34
Airplane Design Limitations (Rocket Propelled)

I'd love to design rocket propelled planes and the turbine engines work quite well for this, but they do have significant limitations.

224.8 lbf thrust limit of the turbine engines
100 oz per minute limit of the turbine engine
500 oz limit of the fuel tank capacity

Without these limitations (or at least higher limitations) one could simulate model rocket motors. Where should one send those feature requests and what is the experience of other users that they actually may get implemented?

Thanks

Oliver
Reply With Quote
  #2  
Old 07-20-2007, 04:01 AM
flyingpigs647's Avatar
flyingpigs647 flyingpigs647 is offline
Registered User
 
Join Date: Jul 2006
Location: nsw, australia
Posts: 166
hi

try using a thruster i think these can put out more thrust and if you adust the fuel tank and fuel consuption you can adust the burn time

if you need more thrust simply ad another thruster

try this and tell me what you think

Alex T
__________________
how can i soar like an eagle if im surrounded by turkeys

My Preflight Check List:left goes left, right goes right, up goes down ......DOWN....ARGGHH

Check out my clubs site - www.dubbomodelaeroclub.com
Reply With Quote
  #3  
Old 07-20-2007, 10:04 AM
brian94066's Avatar
brian94066 brian94066 is offline
Registered User
 
Join Date: Apr 2007
Posts: 517
thrusters have the same thrust as engines, of around 224 lbs

but if you want to make a 10,000 lbs, then add more thrusters, as simple as that

but there's a speed limit of around 447, so i don't think you can go crazy with anything

as for me, i'm pass the speed hungry phase, now it's low, slow, SCRAPE!!
__________________
Amainhobbies.com
Protek R/C
ლ(ಠ益ಠლ)
Reply With Quote
  #4  
Old 07-20-2007, 05:34 PM
Blade Scraper's Avatar
Blade Scraper Blade Scraper is offline
Banned
 
Join Date: Apr 2007
Posts: 1,741
Quote:
Originally Posted by RocketFlyer
I'd love to design rocket propelled planes and the turbine engines work quite well for this, but they do have significant limitations.

224.8 lbf thrust limit of the turbine engines
100 oz per minute limit of the turbine engine
500 oz limit of the fuel tank capacity

Without these limitations (or at least higher limitations) one could simulate model rocket motors. Where should one send those feature requests and what is the experience of other users that they actually may get implemented?

Thanks

Oliver
This isn't really important,i will admit i own atleast 3 rockets,but i prefer planes over anything.i'm fine with what we have,besides rockets are beoring,they just go up then back down,planes are much more exciting.
Reply With Quote
  #5  
Old 07-20-2007, 05:59 PM
brian94066's Avatar
brian94066 brian94066 is offline
Registered User
 
Join Date: Apr 2007
Posts: 517
try to hover with a rocket =P
__________________
Amainhobbies.com
Protek R/C
ლ(ಠ益ಠლ)
Reply With Quote
  #6  
Old 07-20-2007, 11:29 PM
flyingpigs647's Avatar
flyingpigs647 flyingpigs647 is offline
Registered User
 
Join Date: Jul 2006
Location: nsw, australia
Posts: 166
oh ok
yeah well just add more thrusters
but i must admit yeah i like planes better (even know im trying to make a rocket for g3 lol)
but hey they are asy to make and im just learning lol

Alex T
__________________
how can i soar like an eagle if im surrounded by turkeys

My Preflight Check List:left goes left, right goes right, up goes down ......DOWN....ARGGHH

Check out my clubs site - www.dubbomodelaeroclub.com
Reply With Quote
  #7  
Old 07-21-2007, 12:05 AM
RocketFlyer's Avatar
RocketFlyer RocketFlyer is offline
Registered User
 
Join Date: Mar 2007
Posts: 34
Quote:
Originally Posted by Blade Scraper
This isn't really important,i will admit i own atleast 3 rockets,but i prefer planes over anything.i'm fine with what we have,besides rockets are beoring,they just go up then back down,planes are much more exciting.
That's why I build rockets that I can fly back down. That big glider in my avatar is a rocket propelled glider.
Reply With Quote
  #8  
Old 07-21-2007, 12:10 AM
RocketFlyer's Avatar
RocketFlyer RocketFlyer is offline
Registered User
 
Join Date: Mar 2007
Posts: 34
Quote:
Originally Posted by flyingpigs647
oh ok
yeah well just add more thrusters
Alex T
Great suggestion. Never even crossed my mind. The limitations on fuel consumption are still a problem though. I burn about 56 ounces of fuel in 3 seconds. A bit more than the 100 oz per minute limitation
Reply With Quote
  #9  
Old 07-21-2007, 01:13 PM
pawraith's Avatar
pawraith pawraith is offline
Registered User
 
Join Date: Feb 2007
Location: Louisville, KY
Posts: 152
Send a message via MSN to pawraith Send a message via Yahoo to pawraith
here's a lil something to take into consideration, with rockets, your fuel is the engine. whereas with a turbine, the engine's weight is constant. instead of worrying about fuel consumption, you need to look at fuel capacity. set you engine to burn only two ounces of fuel in about 10 seconds, or 100 ounces per minute. my math may be off on the burn rate, but it makes for a more realistic burn time. also, decrease the weight of the engine and you can still have the max thrust, therefore, maintaining the realism. one last thing, make sure you dont hit the speed limit, you loose ALL control when that happens as im sure you already know.

good luck,
chris

P.S. you might also want to lighten the aircraft as well. max thrust maybe around 250 pounds, but what model rocket actually requires that much thrust?
__________________
AKA Wraith in Realflight

Some people smoke crack, I fly R/C Helicopters!

T-Rex 450 se v2 silver
Align 325mm Carbons
DX7 DS285's & Hitec HS81mg w/JR G7703D

Last edited by pawraith; 07-21-2007 at 01:15 PM.
Reply With Quote
  #10  
Old 07-21-2007, 02:29 PM
RocketFlyer's Avatar
RocketFlyer RocketFlyer is offline
Registered User
 
Join Date: Mar 2007
Posts: 34
Quote:
Originally Posted by pawraith
max thrust maybe around 250 pounds, but what model rocket actually requires that much thrust?
Big Rockets do ;-). See attached.
Attached Images
File Type: jpg Big Bird 039s.jpg (88.0 KB, 30 views)
File Type: jpg Big Bird 027s.jpg (58.8 KB, 26 views)
File Type: jpg Big Bird 033s.jpg (106.8 KB, 26 views)
Reply With Quote
  #11  
Old 07-21-2007, 03:01 PM
DrCool DrCool is offline
Banned
 
Join Date: Jun 2007
Location: at my house
Posts: 254
that rocket is cool and big
Reply With Quote
  #12  
Old 07-21-2007, 03:05 PM
pawraith's Avatar
pawraith pawraith is offline
Registered User
 
Join Date: Feb 2007
Location: Louisville, KY
Posts: 152
Send a message via MSN to pawraith Send a message via Yahoo to pawraith
sorry, but i dont believe a rocket the size of what would fit in that model would produce as much thrust as say even a scale B-52 Stratofortress. case in point, see below. and even if it did, the speeds i think you are trying to acheive would rip the wings off.
Attached Images
File Type: jpg b52-2.jpg (67.0 KB, 28 views)
File Type: jpg b52-4.jpg (31.9 KB, 38 views)
__________________
AKA Wraith in Realflight

Some people smoke crack, I fly R/C Helicopters!

T-Rex 450 se v2 silver
Align 325mm Carbons
DX7 DS285's & Hitec HS81mg w/JR G7703D

Last edited by pawraith; 07-21-2007 at 03:10 PM.
Reply With Quote
  #13  
Old 07-21-2007, 04:44 PM
josh0987's Avatar
josh0987 josh0987 is offline
Registered User
 
Join Date: Nov 2006
Location: Nanaimo, BC
Posts: 1,178
Wow! thats a lot of turbine there!
__________________
Code:
Spamming /etc/make.conf.... Done.
Reply With Quote
  #14  
Old 07-21-2007, 04:46 PM
RocketFlyer's Avatar
RocketFlyer RocketFlyer is offline
Registered User
 
Join Date: Mar 2007
Posts: 34
Quote:
Originally Posted by pawraith
sorry, but i dont believe a rocket the size of what would fit in that model would produce as much thrust as say even a scale B-52 Stratofortress. case in point, see below. and even if it did, the speeds i think you are trying to acheive would rip the wings off.
Sorry to disappoint you, but I flew this rocket last weekend at LDRS 26. The motor put out 260 lbf for 3 seconds. The model did weight 71.6 lb at lift-off. The wings did stay on. Unfortunately I did crash the rocket in the end because I stripped the servo horns where they attach to the servo. See below for a couple of pictures and the data from the flight data recorder. If you are interested in the construction of this rocket glider take a look at my www.LVHQ.net/rocketry/bigbird. The site is still under construction, but I will update the info over the next couple of weeks.
Attached Images
File Type: jpg Big Bird 01.JPG (258.7 KB, 23 views)
File Type: jpg Big Bird 03.JPG (155.1 KB, 21 views)
File Type: gif Big Bird RDASs.gif (37.1 KB, 22 views)
Reply With Quote
  #15  
Old 07-21-2007, 06:25 PM
pawraith's Avatar
pawraith pawraith is offline
Registered User
 
Join Date: Feb 2007
Location: Louisville, KY
Posts: 152
Send a message via MSN to pawraith Send a message via Yahoo to pawraith
checked your website and the measurments and that is a big bird. still not as big as the 300Lb B52 but still rather large. and your not going to be able to build a rocket like that in RF, no matter how many engines you put on it i wouldn't think. by the way, your rocket at top speed was doing 177.2727 miles per hour.
__________________
AKA Wraith in Realflight

Some people smoke crack, I fly R/C Helicopters!

T-Rex 450 se v2 silver
Align 325mm Carbons
DX7 DS285's & Hitec HS81mg w/JR G7703D
Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 01:59 PM.