RunRyder RC
 8  Topic Subscribe
WATCH
 1 page 1232 views POST REPLY
HomeAircraftHelicopterMain Discussion › designing a new carbon frame, your views?
11-10-2005 02:30 PM  12 years agoPost 1
Branzzz

rrVeteran

Singapore

My Posts: All  Forum  Topic

i'm thinking of designing a new carbon frame for the raptor 50 as my final year project in my aeronautical engineering diploma...currently i've got a few goals

1. must be lighter yet more rigid than the current plastic frame
2. easy to maintain
3. full push pull CCPM with a central rotation axis to minimise interaction
4. use 3 bearing blocks for the mainshaft with a redesigned main shaft.
5. unconventional engine position to bring the weight closer to the rotor hub.
6. to house the tail servo in the frame
7. to use the same gears, landing skids, head, tail and belt drive as the original raptor.

although i intend this as a research project, i would like to know what additions would you make as if you were designing frames of your own.

Raptor 50V2
OS 50SX-Hyper
GY502/9253
Hitec 6975
Airtronics ERG-VB
JR 3810

PM  EMAIL  Attn:RR  Quote
11-10-2005 05:13 PM  12 years agoPost 2
Laurens

rrKey Veteran

Oegstgeest, NL

My Posts: All  Forum  Topic

I think the way the carbon frames are more important to design.

Edge rotorblades, Scorpion systems

PM  EMAIL  GALLERY  Attn:RR  Quote
11-10-2005 05:21 PM  12 years agoPost 3
scotter

rrApprentice

Winston-Salem, NC

My Posts: All  Forum  Topic

Some random thoughts:
-As you alluded to, centralize the mass as much as possible, especially with the big items, such as engine/pipe, fuel tank, etc.
-Get the fuel tank as near to the cg as possible to minimize cg shift with fuel burn.
-Make the engine very easy to remove, and if possible make it removable without removing the landing gear
-To go along with the previous item, make it easy to align the engine/clutch combo. Slotted mounting holes where necessary, and make it easy to see the clutch to allow for visual checking when aligning the whole thing, both left/right as well as fore/aft.
-Situate the tail servo in the frame such that there is one tail linkage, straight shot back to the tail. I personally am becoming more of a fan of the 'front-mounted' tail servo, i.e. not way out behind the helicopter where it's enveloped in exhaust and oil.
-Firm mounting for the canopy, taking into account the forces due to airflow when in backwards flight
-Crash survivability: in a crash something has to give. Set up the design such that the items that are going to give are cheap and easily replaced. For example, in a hard landing I'd rather see the landing gear break than the frames. Or even better, let fasteners bend or break rather than the more expensive items that they're holding together.
-Obviously servo link geometry is a huge consideration. Setting up the cyclic servos so that linkages can be easily setup for perpendicular at mid-throw.
-Nice big radio tray: this allows for easier mounting of multiple components (such as governor,gyro,governor sensor, volt monitor,etc) as well as adjusting the position of items to get the cg right. Along with this, put slots in the radio tray for running velcro through to hold the battery, rx, etc. firmly in position, both left/right as well as fore/aft.

Wow, didn't think I could come up with that big a list so quickly. All this is a lot to ask for, but these are the things that have become important to me as I build more experience in this hobby. I've seen no heli that hits all these items, but some come close.

PM  EMAIL  GALLERY  Attn:RR  Quote
11-10-2005 05:45 PM  12 years agoPost 4
Ingthor

rrApprentice

Reykjavik - Iceland

My Posts: All  Forum  Topic

if you are planing on re-designing the tail rotor hub and rod, let the rod rotate instead of going back and forth, like the viper 70 and more picture 1

i don't know why, but i like the idea of sending the tail control all the way to the tail in a rotation move instead of back and forth move, guess its easy to keep it friction free
See some examples on viper mods here

PM  EMAIL  GALLERY  Attn:RR  Quote
11-11-2005 04:30 PM  12 years agoPost 5
ChristianM

rrVeteran

Oslo, Norway

My Posts: All  Forum  Topic

I agree with Ingthor. The Tornado and the Revolution was the first helis to use this configuration. In addition to being simple, it also reduces the inertia in tail rotor control system. This will reduce the loads on the tail rotor servo and allow it to react faster and extend its life. The loads due to accelerating the inertia in the control system is much larger than the drag loads.

Christian

Burn fuel, be happy

PM  EMAIL  GALLERY  Attn:RR  Quote
11-11-2005 04:41 PM  12 years agoPost 6
Branzzz

rrVeteran

Singapore

My Posts: All  Forum  Topic

hi guys, thanks for your many replies... i'll update as my group progresses on this.

btw, i originally wanted to mount the engine in an unconventional way above the main spur gear but that has presented some starting problems, like you'd have to hold the starter sideways to the frame, which i think may be quite hard.

ingthor:that's a very interesting heli. i've seen the tail control mechanism on the revolution and tornado and have been impressed. could you post me some links as i would like to find out how the gear train is such that they needed to gear the tail...

Raptor 50V2
OS 50SX-Hyper
GY502/9253
Hitec 6975
Airtronics ERG-VB
JR 3810

PM  EMAIL  Attn:RR  Quote
11-12-2005 02:22 PM  12 years agoPost 7
Ingthor

rrApprentice

Reykjavik - Iceland

My Posts: All  Forum  Topic

well, i don't have many links but i read about it in the newest issue of MHW (December 2005)
Its the Ikarus Viper 70
there is a 2-stage gear reduction from the motor to the main shaft,
the gear ratio between the secondary and the main shaft is 2:1 and the secondary driven gear is a 60T, recommended pinion is 19T giving gear ratio to the head 1:6,3
with the used setup in the article it gives a head speed of 2300
Tail
Speed up gears built into the tail gives 1:4,16 ratio means a high head speed is needed for a powerful tail
gives a tail speed of 9500

Runryder posts
-----

PM  EMAIL  GALLERY  Attn:RR  Quote
11-12-2005 03:19 PM  12 years agoPost 8
Branzzz

rrVeteran

Singapore

My Posts: All  Forum  Topic

very interesting model...carbon washout arms...

Raptor 50V2
OS 50SX-Hyper
GY502/9253
Hitec 6975
Airtronics ERG-VB
JR 3810

PM  EMAIL  Attn:RR  Quote
11-13-2005 11:23 AM  12 years agoPost 9
crankycrankcase

rrNovice

Always on the Move

My Posts: All  Forum  Topic

Sounds like it's gonna be based on the 'CX Avant'.

Hey and why not, that is probably the best 90 Size 3D helicopter currently on the market !!


Derek

PM  EMAIL  Attn:RR  Quote
11-13-2005 12:36 PM  12 years agoPost 10
zoom boy

rrKey Veteran

N.E. Lincolnshire UK

My Posts: All  Forum  Topic

Branzzz, when I did mine I found that the most important part of the project was the documentation rather than the physical object (if you intend to make an example for them) thats where I would concentrate my efforts until the last few weeks then start cutting

Dont know but its probably the same as the course I was on, 70-80% documentation and 20-30% product.

PM  EMAIL  GALLERY  Attn:RR  Quote
11-13-2005 12:40 PM  12 years agoPost 11
Branzzz

rrVeteran

Singapore

My Posts: All  Forum  Topic

hi zoom boy, thanks for the tip.

to tell you the truth, i'm not even in the final year yet, but i really want to start preparing. i've started to make some sketches, but i'm aware that the documentation can only be formally done during the final year, at least that's was what my tutor told me.

i'm interested in how you did yours. could you send me some photos?

crankycrankcase: yup! i got my inspiration from the avant. the only difference is that i want to improve on the control geometry and make this for a 50 sized heli, most likely a raptor. i do not intend to sell it though, just for research, unless it proves to be mega good.

Raptor 50V2
OS 50SX-Hyper
GY502/9253
Hitec 6975
Airtronics ERG-VB
JR 3810

PM  EMAIL  Attn:RR  Quote
11-13-2005 01:07 PM  12 years agoPost 12
zoom boy

rrKey Veteran

N.E. Lincolnshire UK

My Posts: All  Forum  Topic

My project was about trying to further optimize winglet design for a wider range of AoA, while minimizing materials used (weight), all the documentation including photos is probably in a filing cabinet at uni still, so there isnt much chance of getting it (being about 250 miles away)

Sorry.

PM  EMAIL  GALLERY  Attn:RR  Quote
11-13-2005 02:05 PM  12 years agoPost 13
yapjy

rrKey Veteran

Singapore

My Posts: All  Forum  Topic

"The Tornado and the Revolution was the first helis to use this configuration."

Not entirely true. The Kyosho Caliber 60 also uses that type of tail control. I believe the Caliber 60 came out before the Tornado and Revolution.

Branzz, can advise much as I don't own a rappy. But anyway, good luck.

PM  EMAIL  GALLERY  Attn:RR  Quote
11-13-2005 03:01 PM  12 years agoPost 14
damaen

rrVeteran

Umeå, Sweden

My Posts: All  Forum  Topic

No the Caliber 60 used a push-pull configuration and not a rotating rod.

Henrik

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
11-14-2005 12:44 AM  12 years agoPost 15
yapjy

rrKey Veteran

Singapore

My Posts: All  Forum  Topic

Opps, my mistake. Caliber 60 uses a push-pull tail control.

PM  EMAIL  GALLERY  Attn:RR  Quote
11-14-2005 05:43 PM  12 years agoPost 16
w.pasman

rrElite Veteran

Netherlands

My Posts: All  Forum  Topic

Branzz

If you intend to going to sell that, it might be a good idea to stay as close as possible to the original raptor design. That would make an upgrade path possible with the least amount of new parts.

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
WATCH
 1 page 1232 views POST REPLY
HomeAircraftHelicopterMain Discussion › designing a new carbon frame, your views?
 Print TOPIC  Make Suggestion 

 8  Topic Subscribe

Friday, June 22 - 8:08 pm - Copyright © 2000-2018 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online