Glider cradle - RCCanada - Canada Radio Controlled Hobby Forum
RCCanada - Canada's Radio Control Hobby Forum
Sailplanes / Electro-gliders Discuss quiet flight in Canada.

Reply
 
Thread Tools Display Modes
Old 09-25-2016, 10:45 PM   #1
OLD PRAIRIE RED NECK
RCC Supreme Contributor
 
OLD PRAIRIE RED NECK's Avatar
 
I am: MERVIN BURKINSHAW
Join Date: Dec 2010
Location: CORONATION ALBERTA
Radio of choice:
HITEC
# of RCs: 13

Feedback: 8 / 100%
Posts: 4,180
Total Props: 64
Glider cradle


       Remove this ad - become a site supporter!
Adapted the old cradle onto the Senior and tried it out tonight. I went pretty well I must say, no real issues. Got 3 good launches to about 800 feet in then a solder joint on the release linkage started to slip so shut it down for the night.
Attached Thumbnails
Click image for larger version

Name:	piggy backing 0.jpg
Views:	77
Size:	205.7 KB
ID:	1061793   Click image for larger version

Name:	piggy backing 2.jpg
Views:	64
Size:	154.2 KB
ID:	1061801   Click image for larger version

Name:	piggy backing 4.jpg
Views:	64
Size:	84.8 KB
ID:	1061809   Click image for larger version

Name:	piggy backing 6.jpg
Views:	59
Size:	87.9 KB
ID:	1061817  

Click image for larger version

Name:	piggy backing 7.jpg
Views:	57
Size:	23.5 KB
ID:	1061825   Click image for larger version

Name:	piggy backing 8.jpg
Views:	60
Size:	23.3 KB
ID:	1061833   Click image for larger version

Name:	norm's glider 2.jpg
Views:	62
Size:	22.5 KB
ID:	1061841   Click image for larger version

Name:	norm's glider 1.jpg
Views:	50
Size:	24.8 KB
ID:	1061849  

__________________
Hang time does not apply to ceiling fans, light fixtures, overhead door tracks or basketball nets!
OLD PRAIRIE RED NECK is offline   Quick reply to this message.

Sponsored Links - Subscribe to remove this ad.
Old 09-26-2016, 08:01 AM   #2
cassat
RCC Supreme Contributor
 
I am: Dave
Join Date: Jul 2004
Location: P.River,Alberta
Radio of choice:
Airtronics SD-6G
# of RCs: 3

Feedback: 122 / 97%
Posts: 6,179
Total Props: 6
Re: Glider cradle

Thanks for posting Merv
I came across that old RCM article on the cradle last night on the pullinggz blog.
It was mounted on a Senior Falcon, but I was thinking the Senior would be great!
Did you keep the incidence on the glider wing at zero? or plus ?

Dave
cassat is online now   Quick reply to this message.
Old 09-26-2016, 11:07 AM   #3
OLD PRAIRIE RED NECK
RCC Supreme Contributor
 
OLD PRAIRIE RED NECK's Avatar
 
I am: MERVIN BURKINSHAW
Join Date: Dec 2010
Location: CORONATION ALBERTA
Radio of choice:
HITEC
# of RCs: 13

Feedback: 8 / 100%
Posts: 4,180
Total Props: 64
Re: Glider cradle

No problem Dave, glad to share.

I will take the time to check out the incidence today, I just eyeballed it in a hurry last evening trying to beat sundown. I was aiming for zero incidence so we will see. Whatever it is worked well as the climb out was virtually hands off! I have come to think this angle is the most critical part of the cradle build, last time I had it on my Seniorita and I set it slightly positive and struggled to keep the nose down on climb out. I then added a 1/4" shim under the trailing edge of the glider wing and it was too much. I then fought to keep it climbing. I believe the ideal set up would include a way to change that angle to suit different gliders with different airfoils.

There are a couple interesting observations I have made here. One is that is seems to take a bigger powered plane to handle a cradle than to just tow a glider on a line. A Seniorita with a Saito .30 tows up a 3 meter Sagitta with ease while the same plane feels stretched with a 2 meter Sig Riser on a cradle. It's not really a power issue I don't believe so much as an aerodynamic one. The cradle adds 4 things to the formula: side area, weight, drag and aerodynamic interference with the host plane.

The side area issue is partly the glider and feels similar to the effects adding floats does to turns on a powered plane. Making the cradle from something like music wire or aluminum tubing would help that.

The weight and drag will always be in finding the right compromise with strength.

The downwash from the glider wing can be lessened by making the cradle higher but then you move the center of drag up causing more pitch up when power is added so that is a compromise too!

Out of all the methods we have tried in launching a pure glider this appears to be the one with the least risk and easiest to manage in the air. Towing with a line would be next with the high start and winch launches being the most risky.

But towing is by far the most fun and most visually pleasing in my experiance!
__________________
Hang time does not apply to ceiling fans, light fixtures, overhead door tracks or basketball nets!
OLD PRAIRIE RED NECK is offline   Quick reply to this message.
 
Old 09-26-2016, 01:21 PM   #4
OLD PRAIRIE RED NECK
RCC Supreme Contributor
 
OLD PRAIRIE RED NECK's Avatar
 
I am: MERVIN BURKINSHAW
Join Date: Dec 2010
Location: CORONATION ALBERTA
Radio of choice:
HITEC
# of RCs: 13

Feedback: 8 / 100%
Posts: 4,180
Total Props: 64
Re: Glider cradle

It's one degree positive Dave.
__________________
Hang time does not apply to ceiling fans, light fixtures, overhead door tracks or basketball nets!
OLD PRAIRIE RED NECK is offline   Quick reply to this message.
Old 09-27-2016, 07:03 PM   #5
rome
RCC Senior Contributor
 
I am: Romeo R
Join Date: Dec 2004
Location: toronto
Radio of choice:
Futaba
# of RCs: 10

Feedback: 44 / 100%
Posts: 712
Total Props: 3
Re: Glider cradle

was this from a kit, or scratched built.

I always wanted to build of this

thanks
__________________
maac #38176
sport flyer
rome is offline   Quick reply to this message.
Old 09-28-2016, 06:22 AM   #6
OLD PRAIRIE RED NECK
RCC Supreme Contributor
 
OLD PRAIRIE RED NECK's Avatar
 
I am: MERVIN BURKINSHAW
Join Date: Dec 2010
Location: CORONATION ALBERTA
Radio of choice:
HITEC
# of RCs: 13

Feedback: 8 / 100%
Posts: 4,180
Total Props: 64
Re: Glider cradle

Scratch built.
__________________
Hang time does not apply to ceiling fans, light fixtures, overhead door tracks or basketball nets!
OLD PRAIRIE RED NECK is offline   Quick reply to this message.
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the RCCanada - Canada Radio Controlled Hobby Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

Member names may only be composed of alpha-numeric characters. (A-Z and 0-9)

!!ATTENTION ADVERTISERS!! If you intend on advertising anything on this forum, whatsoever, you are required to first contact us here . Additionally, we do NOT allow BUSINESS NAMES unless you are an Authorized Vendor. If you own a business, and want to do sales on this site via posting or private message, you will need to follow the rules. Shops, Stores, Distributors, Group Buys without being authorized will see your account terminated.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Your Name
Your first name and last initial is required if you plan on using the forum.
Location
Which city & province you live in. This is mandatory for classified listings.
Radio of choice?
Which radio is your current favorite to use?
Number of RC Vehicles?
How many boats, cars, planes do you own?

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
vBulletin Message

Thread Tools
Display Modes

Forum Jump


All times are GMT -5. The time now is 10:38 AM.


vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.