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Aug 21, 2016, 02:56 AM
flyin' fool
goldguy's Avatar
Thread OP

Boomer Jr and Sr.............Slope Sensations

My version of the Chinook/Red Herring/Boomer EX2 is a 4.5 ounce 28" span sloper for those light lift days. The root cord, including the 1" elevons, is 10.75", the tip is 5 and it's balanced at 4.2"

The wing is in EPP with a pivot cut PW51 airfoil, other bits in 2mm Depron and some thin styrene. Lam film is the covering of choice for the wing, tape for the rest and a weed whacker line LE.

Control is by 5.6 g DS MG servos, a 4 ch Orange and 4 X 220 mAh 2/3 AAA NiHM.

It's fast for generating lift in light winds and flies much like my bigger Wisels. You can actually do aerobatics in light wind as it retains it's energy well, like all other PW51 birds. But what's really amazing is, it can fly up a storm in up to 30 kph winds WITHOUT ballast. After that with some lead on board it's rock n' roll big time.

Put a smile on your face when the others are grounded, a big smile.

Check page #4 where you'll find the 860mm/34" version.
Last edited by goldguy; Feb 03, 2018 at 01:37 AM.
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Aug 21, 2016, 05:04 AM
“There’s no place like Foam”
gpw's Avatar
Makes one wish we had slopes ...
Latest blog entry: Lost plans
Aug 21, 2016, 08:42 AM
Retired CAD guy
birdofplay's Avatar
I hear you GPW !
When I was out in the NW I had access to a 360' overlook of the Columbia river estuary
from about 40 miles inland. On a clear day I could make out some of Astoria , Oregon.

It was a terrific place to slope IMHO and I really MISS IT !
Aug 21, 2016, 08:50 AM
Registered User
DAN7160's Avatar
So many planes and so little time
Aug 21, 2016, 11:10 AM
“There’s no place like Foam”
gpw's Avatar
Dan , just have to squeeze in more planes ... hahaha
Latest blog entry: Lost plans
Aug 23, 2016, 01:09 AM
flyin' fool
goldguy's Avatar
Thread OP
The Boomer will fly in 'Whipit' only wind.
Aug 26, 2016, 11:32 PM
Steve 0's Avatar
Did you put any dihedral in it?
Aug 27, 2016, 03:30 AM
flyin' fool
goldguy's Avatar
Thread OP
Originally Posted by gpw
Makes one wish we had slopes ...
When the Alula was the flavor of the week we all had one and used to slope off the logs on a local beach after a SAL. Amazing and lots of fun testing your flying skills.

Then we started combating them................... now they are all history.

Hail to EPP!!
Aug 27, 2016, 12:29 PM
flyin' fool
goldguy's Avatar
Thread OP
Originally Posted by Steve 0
Did you put any dihedral in it?
Flat on the top.
Aug 28, 2016, 01:58 AM
jonesymj's Avatar
Originally Posted by goldguy
now they are all history.
I still got mine...
Aug 29, 2016, 02:39 PM
Registered User

More info please!

Hi Frank,

This is exactly the kind of glider I need for my puny local slopes, so am interested in more details:

(Updated with responses from Frank)

Use whatever you have and increase the wing area if necessary to keep the loading down to - 3.0 oz. per sq. ft

Density of EPP? - 1.9 lbs/ft3

Pivot cut with one "outside" root PW51 airfoil template
Airfoil template made of arborite/formica laminate scraps. Alternative is thin aluminum sheet sold as window flashing at hardware stores. Cut out with heavy duty scissors or tin snips.
After the wing is hot wired, trim the TE of the airfoil as needed to leave a 2 mm TE to allow attachment of 2 mm thick elevons.
If possible provide a plan view of the block of EPP and pivot cutter set up ? Frank's setup is in storage. Google pivot cutter.

Finger holes for launching, located on the underside of the glider, are located just back from CG, made with soldering iron, using a large washer with large inside dia hole.

LE weed wacker line is .065". Cut off length equal to LE, hang with a weight on the end, heat with hot air gun to straighten line as needed.
Cut vee in LE of wing to fit .065 "weed wacker line. Insert weed wacker line into the vee, and CA in place.

Elevons and fin are 2 mm thick Depron
Elevons 13 7/8" long x 1" deep
Fin base 5", height 3.25, set back from base to tip 3.5". Fin is mounted 7" back from LE of wing.
Elevons and fin covered with clear packing tape (cheap thin stuff)
Laminating film 1.7 (mil) I think
Buy laminating film at shops that do laminating, CrashTest Hobby, Alofthobbies (new stuff), etc.
No re-enforcement of the fin or fin to wing attachment.
Hot glue the fin to the wing
Elevons hinged with single strip of Duck brand HD crystal clear.

Thin styrene plastic used for electronics hatch.
How thick is the styrene? .4 mm? = .015"
Get thin styrene from HS that sells train stuff.

5.6 g DS MG servos
Install the servos in the wing forward of the CG.
Hot glue the servos in the wing.

Push rods are 0.047" dia music wire (K&S #502

What horns do you use?
If horns are scratch-built, what are rough dimensions.

Rx is R410 DSMX or R610V2 DSM2 RX I only see that available from HK International. Do you have a N. American source?

Flat battery pack (4 X 220 mAh 2/3 AAA NiHM) Team Losi from HS
Battery charging and on/off "switch" wiring diagram shown below in Post #13.
Example battery packs:

Battery/Rx compartment is located just behind the LE
Use soldering iron to cut out battery/Rx compartment.
Cover with thin foam and tape?

See craft store for tape and lettering?
Tape from Tape Brothers on eBay.

Lastly, what is the build order?

Any sketches of wing, fin, etc with dimensions would be appreciated.
Any photos, especially of the battery/Rx bay and hatch would be helpful.

Sorry for all the questions!
I plan to do a build log with photos using the info you provide.
I continue to admire you building skills.
I have a lot to learn.


Renton WA
Last edited by rcflydad; Apr 02, 2017 at 05:21 PM. Reason: Add more detailed questions I didn't think of when first posting.
Aug 29, 2016, 06:56 PM
flyin' fool
goldguy's Avatar
Thread OP
Will answer your queries soon.

In the meantime..................... Yesterday I was flying in 20 plus knot winds with the big boys and didn't even have to add ballast. Amazing!! I was able to speed past all but a small 30" span 30 ounce Wasp. Even took out a 36" Wisel while mixing it up with the combat crowd, mostly Wicked Wings from HK.

I'm able to 'fly in your face' right on the edge just like I was indoor flying, continuous loops, rolls and inverted, all with ease. And that's in light and heavy winds/lift. The most fun sloper I've built so far.

Now everyone wants me to cut Boomer cores for them. I think I've created a monster.
Last edited by goldguy; Aug 29, 2016 at 07:12 PM.
Aug 29, 2016, 07:23 PM
flyin' fool
goldguy's Avatar
Thread OP
The on/off/charge plug ........................
Last edited by goldguy; Aug 30, 2016 at 01:38 AM.
Aug 29, 2016, 08:33 PM
When pigs fly rc
rcrich's Avatar
Sounds great!
Aug 29, 2016, 11:02 PM
Professional amature
Gee Frank!! I have to build this sloper now!!!

I was actually considering building a fuse-less wisel but the BOOMER Jr looks the ticket.

For a power system I use Lithium Ion 18650 2800mAhr cells out of old laptop battery packs to power my slopers. They are about 3.9vdc nominal so I use them in parallel to power my Lemon RXs and EMAX ES08MAII metal gear servos. The Lemons are DSM2 full range, small/light, cheap, fast delivery and not a clone. These EMAX ES08MAII servos are quick and the only servo that I have never killed and reasonably priced on Ebay.

I have run one of my slopers on a single 18650 Lithium Ion battery and it has not needed to be charged all summer. The load on it is the Lemon RX and two EMAX servos with no BEC needed. This with Frank's servo switch/charge port and you have a great set-up.


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