SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Mar 03, 2013, 05:33 PM
Registered User
United States, IN, Hammond
Joined Jan 2013
663 Posts
I may try a 370 brushed gearbox before I'm through playing around.
Ken USA is offline Find More Posts by Ken USA
Reply With Quote
Sign up now
to remove ads between posts
Old Mar 03, 2013, 06:02 PM
M0unt@in M0del$ minion
turbojoe's Avatar
United States, AZ, Mesa
Joined Jul 2002
7,325 Posts
Quote:
Originally Posted by Ken USA View Post
I may try a 370 brushed gearbox before I'm through playing around.
You'd be surprised at just how well she'll fly even on that combo. Most of us started with the 350 and KAN cells. Come to think of it I still have a pile of those cells in a box somewhere. I should probably have them recycled......

Joe
turbojoe is offline Find More Posts by turbojoe
Reply With Quote
Old Mar 03, 2013, 07:03 PM
United States, CA, Santa Rosa
Joined Mar 2011
883 Posts
My favorite combo is a turnigy 2205 1350 kv swinging a 9x4.7 slow fly on 3s.
asosestrom is offline Find More Posts by asosestrom
Reply With Quote
Old Mar 04, 2013, 01:40 PM
Registered User
United States, IN, Hammond
Joined Jan 2013
663 Posts
That motor looks like a great choice
Ken USA is offline Find More Posts by Ken USA
Reply With Quote
Old Mar 05, 2013, 07:54 AM
Registered User
United States, IN, Hammond
Joined Jan 2013
663 Posts
Rafe
Received blue wonder and 20-26 also ordered eps dx 370 and black diamond 301 to try out.
I tried to maiden SB Sunday, but there was no one to buddy box with. Another day.
I hope to weigh up the plane with the various combos this week.
Ken USA is offline Find More Posts by Ken USA
Reply With Quote
Old Mar 14, 2013, 03:10 PM
Registered User
Joker 53150's Avatar
United States, WI, Muskego
Joined Sep 2012
851 Posts
The weather was finally good enough to give my Switchback it's maiden flight today (30 degrees, 6-9 MPH winds, but sunny!). I brought along min Mini Skywalker to warm my thumbs up before flying the Switchback, but that flight lasted about 30' due to either major pilot error or mechanical failure...

One plane down, one to go. That always makes me nervous.

I had the parking lot to myself at the local park today, so I walked to the center of the lot and lined the plane up into the wind. With little more than 1/2 throttle it climbed up quickly and continued to climb heavily. Too heavily, so I quickly gave it as much down trim as possible and brought it in for a quick adjustment. Luckily for me I was able to get it down in one piece on my first official pavement landing. This was with the suggested CoG at about 1/2" behind the spar. After adjusting the CoG I ran two 1000mAh packs through it. First at 7 minutes and the second for 9-1/2. Looks like my "sweet spot" in the cold weather will be about 9 minutes.

The flights were very calm, and the only issue I have is that the bottom and top look the same so it's nearly impossible to tell which way is up! A few times I had close calls, but keeping it high enough to fix my errors saved me.

As said, this was the first time I've landed on pavement and I'm very happy with myself as I did a half-dozen landings and all were fine. With a little headwind one of the landings was shorter than the width of the parking space I touched down in! It almost hovered as it came in! I do need to adjust the landing gear, as the whole assembly would rock on the mounting screw a little. I'm tempted to put a drop or two of glue in there to secure it permanently, but permanent is such a long time...

A little less expo on the ailerons is also needed. Less elevator travel would be good as well, as it REALLY moved the plane with authority! Rudder was good.

My hardware for the plane is as follows:
HK 9 gram servos
HK 18-20A ESC
Orange 6 channel RX
Turnigy ER9X TX
8x4.3 prop
3S, 1000mAh battery (I get about 6Amps and 67 Watts with this setup).
The motor is also from HK, model AX 2308N, 1100kv. This comes with a mounting bracket designed to stick-mount so it worked great with the stock Switchback motor mount setup. I'm not thrilled with the threaded prop shaft, but it worked so I can't complain much.

The motor/prop combination works well, but it seems like anything above 2/3 throttle is pretty flat, no extra power is noticed. Not a big deal, as I want to get more time with the plane before worrying about speed. I'm guessing it's just the prop design limiting the motor, as it's a slow-flight style prop.

If the weather holds out I'll take the plane back out tonight for a few more flights. Maybe I can talk my wife or kids into going along to take some video for me.
Joker 53150 is offline Find More Posts by Joker 53150
Reply With Quote
Old Mar 14, 2013, 03:33 PM
Registered User
machinate's Avatar
Joined Jan 2010
913 Posts
Quote:
Originally Posted by Joker 53150 View Post
The motor/prop combination works well, but it seems like anything above 2/3 throttle is pretty flat, no extra power is noticed. Not a big deal, as I want to get more time with the plane before worrying about speed. I'm guessing it's just the prop design limiting the motor, as it's a slow-flight style prop.
Try calibrating your ESC. Most likely the ESC is delivering full power before you run out of stick travel, simply because of a programming mismatch.

Other than that, it sounds like a great first flight! I really need to get mine finished this spring.
machinate is offline Find More Posts by machinate
Reply With Quote
Old Mar 14, 2013, 04:03 PM
Registered User
Joker 53150's Avatar
United States, WI, Muskego
Joined Sep 2012
851 Posts
Might just be prop flex. Could also just be the cold weather made it hard for me to see any difference while I shivered in the cold!
Joker 53150 is offline Find More Posts by Joker 53150
Reply With Quote
Old Mar 14, 2013, 06:25 PM
Registered User
United States, IN, Hammond
Joined Jan 2013
663 Posts
"Luckily for me I was able to get it down in one piece on my first official pavement landing"
Great report! I'm still waiting for my maiden. Nervous, too.
Ken USA is offline Find More Posts by Ken USA
Reply With Quote
Old Mar 14, 2013, 06:37 PM
Registered User
Joker 53150's Avatar
United States, WI, Muskego
Joined Sep 2012
851 Posts
Quote:
Originally Posted by Ken USA View Post
"Luckily for me I was able to get it down in one piece on my first official pavement landing"
Great report! I'm still waiting for my maiden. Nervous, too.
Thanks. Once it was trimmed it was very easy to fly - dare I say even easier than my Hobby Zone Super Cub? It certainly flew slower. I still haven't tried the SC with a TX that has expo, so maybe the Switchback just had an unfair advantage in easy flight - I'll know for sure when I try the SC out with the new TX. As mentioned this is the first time I've landed on anything other than grass, and after a few landings and a few practice approaches I had no worries about it. There were a few small gusts that kept me alert, but the plane handled them well.

The manual calls for CoG at 1/2" behind the spar to start. For me this appears to have been too far back since it was constantly trying to climb. My next flight will have the CoG moved forward to the back edge of the spar. That, along with the programming changes I'll make to the TX will hopefully pay off well!

Since these flights I've now added some more red to the bottom of the plane for visibility. I didn't want to do it, but knowing top from bottom is kind of important. I've also secured the gear a bit so the landing gear doesn't wobble when I land.

The pic is of the plane just after it's first flight, and possibly the first time it's been outside. Next time I need to remember to take pics BEFORE the flight instead of after, just in case!
Joker 53150 is offline Find More Posts by Joker 53150
Reply With Quote
Old Mar 14, 2013, 07:16 PM
Registered User
Joined Jan 2009
7,643 Posts
Congrats on the maiden. I'm not nervous when doing a maiden flight on any Mountain Models plane. Haven't had one yet that didn't fly right, from the word "go." Having seen your attention to detail, I'm not at all surprised at your success.

FWIW, it took me a year or two before I was confident enough to fly over pavement.

Aside from obvious dumb-thumb moves, the greatest danger to your Switchback may come from windy-day landings. She's actually nimble enough to fly in gusty conditions, but you have to be really careful bringing her in.
rafe_b is offline Find More Posts by rafe_b
Reply With Quote
Old Mar 14, 2013, 07:43 PM
Registered User
Joker 53150's Avatar
United States, WI, Muskego
Joined Sep 2012
851 Posts
I did notice the gusts keeping things interesting at slow landing speeds. Not a major issue although a little more airspeed would have been good to keep airflow over the wing when the wind died.

On a dead calm day landing should be great!
Joker 53150 is offline Find More Posts by Joker 53150
Reply With Quote
Old Mar 14, 2013, 08:16 PM
Registered User
Joined Jan 2009
7,643 Posts
The Switchback is so light and agile, it's like a 3D or an indoor plane -- if you want to, you can keep it within 50 or 100 feet of yourself for the duration of the flight. It requires almost no take-off roll, and does a beautiful dead-stick landing if need be.

When the wind is calm, at any rate... These days I have other planes to fly when the wind kicks up. No point risking the Switchback.

Harping on this because of the incidents I had with my first Switchback (involving big wind) which led to its demise. Classic psychological projection.
rafe_b is offline Find More Posts by rafe_b
Reply With Quote
Old Mar 14, 2013, 08:32 PM
United States, CA, Santa Rosa
Joined Mar 2011
883 Posts
Nice work on the maiden Joker. Mine had the same climbing issue as you describe. I put in a little down thrust on the motor and that worked great for me.
asosestrom is offline Find More Posts by asosestrom
Reply With Quote
Old Mar 14, 2013, 08:52 PM
M0unt@in M0del$ minion
turbojoe's Avatar
United States, AZ, Mesa
Joined Jul 2002
7,325 Posts
You know I can't remember ever having heard of a failed SwitchBack maiden. At least one that wasn't dumb thumbs related. Glad you continued the success string. It just gets better as you get her tweaked to your liking.

I love that T-28/T-34 covering scheme. I'm going to have to blatantly steal the idea for the next SwitchBack I build. It really looks awesome on this airframe.


Joe
turbojoe is offline Find More Posts by turbojoe
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
FS: Mountain Models Switchback Sport Package-NIB PDX Slope Pilot Aircraft - Electric - Airplanes (FS/W) 5 Aug 02, 2002 11:57 AM
Mountain Models Switchback Service butter_fingers Parkflyers 0 Jun 17, 2002 02:05 PM
AeroMicro Carries Mountain Models Switchback Now. GoEFlight Vendor Talk 0 May 21, 2002 02:45 PM
Mountain Models Switchback Steven9026 Parkflyers 27 May 20, 2002 05:01 PM
Mountain Models Switchback 3D J Bergsmith Parkflyers 330 Apr 08, 2002 12:18 PM