RE: Sundowner 50 Arf

RE: Sundowner 50 Arf
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RE: Sundowner 50 Arf - 4/4/2008 10:09:45 PM

bob27s

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From: Cleveland, OH, USA
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Maybe so.... does take a lot of energy to puch a hole in the sky and reach 150mph with anything..... and this is not a small plane.

And you are correct, prop selection is important. Im not sure a 12" disk is the answer for speed though.

I fly some electric, but Im not really a fan. I'm in this sport for the engines when it comes down to it... and I like building too.

I'm expecting the 9" diameter to be the right solution for a speed bias and otherwise balanced performance. 60Lx and 10x6 appears to be good for 130 range. I think an approach toward a bit higher rpm and getting the disk area down will do better ----- more of a pylon setup may be in order.

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Jett Engineering - Engine Mfg Support Forum Host

(in reply to z06kal)

Post #: 226

RE: Sundowner 50 Arf - 4/4/2008 10:49:01 PM

z06kal

Posts: 134
Joined: 6/25/2004
From: Woodland Hills, CA, USA
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Bob I think the plane is too draggy for a 9". Probably similar in drag to something like the Bobcat 50 which someone ran a 9x6 taching 26,000rpm via high power electric and the plane barely went 80. I doubt something smaller than 11" will get you to 150mph. Probably more like 12" minimum. IN which case not sure how many IC engines can spin a 12x12" prop at 16,500. THat would be 150mph through a 12x12 with 80% slip.

Maybe one of these days I'll pickup a Sundowner 50 and give it a shot. Isn't more than $450 for the power system which is probably not much more expensive than an IC engine that can do the above.

< Message edited by z06kal -- 4/4/2008 10:53:05 PM >

(in reply to bob27s)

Post #: 227

RE: Sundowner 50 Arf - 4/8/2008 4:16:33 AM

pilotoe

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Joined: 2/14/2008
From: sanford, FL, USA
Status: offline

with the jett 90lx on the Sundowner 50, and a APC 11 x 8, i turned 14,300 and 133mph on the radar gun. had a slight problem on landing last week so while the Sundowner was in for repair, i stuck the 90lx on my Bobcat 52 with an APC 11 x 7 pusher and turned 115 mph....with fixed gear. i'm building a new Bobcat with heavy duty retracts. i'm hoping for 125 mph.

(in reply to z06kal)

Post #: 228

RE: Sundowner 50 Arf - 4/8/2008 6:05:51 AM

Yellowsierra02

Posts: 67
Joined: 3/16/2007
From: Andrews, NC, USA
Status: offline

quote:

ORIGINAL: bob27s

Maybe so.... does take a lot of energy to puch a hole in the sky and reach 150mph with anything..... and this is not a small plane.

And you are correct, prop selection is important. Im not sure a 12" disk is the answer for speed though.

I fly some electric, but Im not really a fan. I'm in this sport for the engines when it comes down to it... and I like building too.

I'm expecting the 9" diameter to be the right solution for a speed bias and otherwise balanced performance. 60Lx and 10x6 appears to be good for 130 range. I think an approach toward a bit higher rpm and getting the disk area down will do better ----- more of a pylon setup may be in order.

Hey Bob,

Have your heard anything new about the Jett 60lx setups on this plane. I wonder what the fastest speed is so far.

Justin

(in reply to bob27s)

Post #: 229

RE: Sundowner 50 Arf - 4/8/2008 4:17:00 PM

z06kal

Posts: 134
Joined: 6/25/2004
From: Woodland Hills, CA, USA
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Pilotoe I'm running a 12x12 @ 11,400rpm via electric on my bobcat 50. It does 118mph level flight like that on radar. I do have retracts but I honostly feel the retracts have no drag advantage on this plane as the retract setup severely disrupts the airflow across the fusalage and wings. I'm gonna be putting a higher KV motor on there and take it up to about 14,000rpm on the 12x12. Maybe pickup another 20mph if I'm lucky.

(in reply to Yellowsierra02)

Post #: 230

RE: Sundowner 50 Arf - 4/8/2008 4:49:50 PM

bob27s

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From: Cleveland, OH, USA
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quote:

ORIGINAL: bob27s

Here is the sundowner 60LX setup Dub and Mike put together. Pretty much in line with what I described way up earlier in the thread, and similar to the photos posted of another 60LX powered bird.

Dub is going to offer a "sundowner" package that includes the exhaust spacer/angle and an engine mount that accomplishes the rotation and offset from the firewall.

Note how clean this setup is. Muffler enters the fuselage. A baffle/tray/deflector is build inside of the fueslage to enclose the muffler area a bit. Exhaust exits the bottom of the plane. Small cutout is required in the cowl to clear the foward part of the muffler.

More photos once they get it in the air this weekend.

Ok, I have some flight data to share....

Setup was the 60LX engine, 8oz bubble-jett tank, 10x6 APC prop (also flew with a 9x7 zinger). Engine backed down 800-1000 rpm off peak for launch.

Honest level flight speed, little to no wind, 130mph. Several level passes of 133, 134, 135. In a shallow dive entering the radar cracked 140 a bit.

It is expected that a bit better speed will come from using a 9x8 or 9x9. Neither was tested this weekend.

(Radar is a fixed mount, remote display that is used for testing the racing setups)

Aircraft and engine combination was extremely smooth, pattern ship type performance, and the plane flew great in all aspects of flight, take-off and landing.

I will post a few photos when Dub sends them along

Bob

_____________________________

Bob Brassell
Jett Engineering - Engine Mfg Support Forum Host

(in reply to bob27s)

Post #: 231

RE: Sundowner 50 Arf - 4/8/2008 5:33:25 PM

russm

Posts: 339
Joined: 8/6/2006
From: waukegan, IL, USA
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how does the sundowner compair size and weight wise to the toni. i thought they were about the same size. i have my 60lx on a h9 u-stick. when i put a 9 size prop on it i loose speed. glad to here about a ext. package w/ this engine. the problem has always been to get the muffler to fit w/out a lot of ext,s. hey patz, see you next fall w/ my toni 90lx setup. finally got it dialed in.

(in reply to bob27s)

Post #: 232

RE: Sundowner 50 Arf - 4/8/2008 6:19:48 PM

patzane

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Joined: 11/11/2005
From: Glendale, AZ, USA
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Sound get Russ. We had our 1/8 Air Force event and it was a blast. There are a few Sundowner 50 and 1 bigger Sundowner. There are about 2 Toni's . I flew my F-16, Sundowner, and Piper Cub.

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Post #: 233

RE: Sundowner 50 Arf - 4/8/2008 6:37:01 PM

z06kal

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Joined: 6/25/2004
From: Woodland Hills, CA, USA
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bob27s what kinda RPM are you taching with that Jet 60lx? 130mph on a 10x6 works out to nearly 23,000rpm with 0% slip. I'm actually surprised that a 10" disc worked out this well on the Sundowner. It must be more slippery than it appears. I still think, however, it will be slower on the 9". Only one way to find out tho

.

< Message edited by z06kal -- 4/8/2008 6:39:17 PM >

(in reply to patzane)

Post #: 234

RE: Sundowner 50 Arf - 4/8/2008 7:37:32 PM

russm

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From: waukegan, IL, USA
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gotta think the 90lx would be a better engine for the sundowner. pat, what kind of speed are you geting w/ the 91fx? somewhere there has to be a power to weight ratio that makes sense on any given plane. if you have to add a lot of weight to cg the plane, then what has anyone really acomplished?

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Post #: 235

RE: Sundowner 50 Arf - 4/9/2008 4:35:03 AM

Yellowsierra02

Posts: 67
Joined: 3/16/2007
From: Andrews, NC, USA
Status: offline

quote:

Ok, I have some flight data to share....

Setup was the 60LX engine, 8oz bubble-jett tank, 10x6 APC prop (also flew with a 9x7 zinger). Engine backed down 800-1000 rpm off peak for launch.

Honest level flight speed, little to no wind, 130mph. Several level passes of 133, 134, 135. In a shallow dive entering the radar cracked 140 a bit.

It is expected that a bit better speed will come from using a 9x8 or 9x9. Neither was tested this weekend.

(Radar is a fixed mount, remote display that is used for testing the racing setups)

Aircraft and engine combination was extremely smooth, pattern ship type performance, and the plane flew great in all aspects of flight, take-off and landing.

I will post a few photos when Dub sends them along

Bob

Thanks for the Update Bob! Let us know when the 9 x 9 or Other props are tested. It looks like if the 10 x 6 prop pulled that kind of speed then it should really scoot on a 10 x 8 or 9 x 9! I think im forgetting something...? Oh if possible... We want Video!!! haha

< Message edited by Yellowsierra02 -- 4/9/2008 4:39:54 AM >

(in reply to bob27s)

Post #: 236

RE: Sundowner 50 Arf - 4/9/2008 5:24:05 AM

patzane

Posts: 587
Joined: 11/11/2005
From: Glendale, AZ, USA
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Russm I don't know what speed the Sundowner with the OS 91. If I had to guess I would say 100+. As for as weight I just moved my battery around to get the CG correct. We have a few guys at the field with a YS 91, but it has not seen the air yet. I like to see the match up a match up between an OS 91FX, YS 91 or 110, and Jett 61 or 91, Who you think will win?

quote:

ORIGINAL: russm

gotta think the 90lx would be a better engine for the sundowner. pat, what kind of speed are you geting w/ the 91fx? somewhere there has to be a power to weight ratio that makes sense on any given plane. if you have to add a lot of weight to cg the plane, then what has anyone really acomplished?

_____________________________

Don't go where the path leads
But go where there is no path

(in reply to russm)

Post #: 237

RE: Sundowner 50 Arf - 4/9/2008 3:07:44 PM

learjet45xp

Posts: 86
Joined: 3/22/2007
From: , FL, USA
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I know my money would be on the Jett 60LX. The .90LX would need a larger prop and for a plane this light I don't think it would be utilized very well. I think Dub got it right with the .60LX...low weight, right size prop, and very high RPM.

(in reply to patzane)

Post #: 238

RE: Sundowner 50 Arf - 4/9/2008 4:27:48 PM

bob27s

Posts: 4712
Joined: 4/9/2002
From: Cleveland, OH, USA
Status: offline

quote:

ORIGINAL: Yellowsierra02

quote:

Ok, I have some flight data to share....

Setup was the 60LX engine, 8oz bubble-jett tank, 10x6 APC prop (also flew with a 9x7 zinger). Engine backed down 800-1000 rpm off peak for launch.

Honest level flight speed, little to no wind, 130mph. Several level passes of 133, 134, 135. In a shallow dive entering the radar cracked 140 a bit.

It is expected that a bit better speed will come from using a 9x8 or 9x9. Neither was tested this weekend.

(Radar is a fixed mount, remote display that is used for testing the racing setups)

Aircraft and engine combination was extremely smooth, pattern ship type performance, and the plane flew great in all aspects of flight, take-off and landing.

I will post a few photos when Dub sends them along

Bob

Thanks for the Update Bob! Let us know when the 9 x 9 or Other props are tested. It looks like if the 10 x 6 prop pulled that kind of speed then it should really scoot on a 10 x 8 or 9 x 9! I think im forgetting something...? Oh if possible... We want Video!!! haha

I will ask if Mike and Dub can toss together a video when time permits.

I am not sure about the 90LX. I know at least a couple people have tried it. With a 10x10 on it, it can get up around 16,000 rpm and we know an 11x8 gets up over 15,000 without a problem. But there is more complexity ---- muffler will likely have to be entirely external too.

Can the airframe handle it?

And, is it worth it to put a 90LX up front? This is a semi-scale ARF aircraft. Sure, nice plane..... flys well. Seems to be well designed. The 60LX, an OS 55 or a Webra 50/55 would be a great match. Nice here to see the variety of engines being tried both 2c and 4c. Give good perspective.

Personally I would rather toss a 90LX in an old Tipo .. would enjoy it more in the long run, and its pleanty fast.

___________