Slowest practical lap time for Flite Streak

[Kim Mortimore]

A friend of mine is using a FS ARF to learn the more difficult parts of the pattern.  We are curious what the slowest practical lap time is for this plane (in good air--light breeze), and what line length  would be best for this lap time.

Thanks,
Kim Mortimore

[Elwyn Aud]

That would depend somewhat on line length. I've got a Streak on 60 foot lines and I tend to like it around a 4.5 second lap speed. They were made to fly fast! I think 5 second lap speed would be as slow as I would want to go.

[Paul Taylor]

I attend to agree with Elwyn.
The FS is a fast plane and seems to fly better going fast. You can slow it down but it would be lite on the lines. Shorter would be better maybe to keep the lack out of the lines. I would not go shorter then 52ft.

[Bill Heher]

I found that my FS ARFs w / OS .25 FP liked around 5 sec. Slower and they got loose overhead, but at around 5 they grooved nice and still very manueverable. 1st plane I was able to do multiple outside loops and horizontal 8s with confidence. Too bad the fuse is so fragile, the wing and tail from the ARF are plenty good / strong for sport flying and training. The front end just doesn't hold up to normal hard landings / doinks.

58-60 foot .015 lines were pretty good,  and I flew it a few times on .012" X 58' and really liked it, but the weeds / grass at the secret flying site kinked them pretty easily, and then one day it turned in on take-off and ate them in the prop.

[Steve Helmick]

Kim...Power is?  One way to assure a slower lap time is to add more "power" (THRUST). Propeller matters a lot, however, and I'm not all that convinced that "lap time" is as important as the basic gut feeling that the model is flying at a comfy speed. Sound can play tricks, as can other sensory perceptions. Getting the trim right will also help the model fly slower. Work on everything between the handle and the prop nut!  Steve

[phil myers]

So does that mean larger or smaller diameter and or larger/smaller pitch in prop size?
I'm thinking a smaller prop speeds up the engine but slows the plane down?
Cheers Phil

[Dennis Moritz]

Try it. Fly it. Not an abstract issue. It all depends. I'd put the watch away and judge needed speed by feel of the controls and your comfort level. Streaks can be flown effectively at stunt trainer speeds. George's airfoil etc. having a bit of magic in it. My ARF Streak powered by an LA25 was a great learning combo. Got me through beginner. Didn't worry much about prop etc, believe I was using a 9x4 so and so. Engine ran in a mild 2-stroke. Lines were .015 x 58 or 60. Forgiving, easy to fly. First off the plane needs to be in trim. All surfaces aligned, right tip weight, lead outs etc. in the right place. Any warps need to be fixed. Do the basics first. Plane might get loose overhead if the maneuver is flown too tight, when flown at the right size, there's enough tension. Good Luck. I liked my Streak. Yep. Mine too suffered from the weak nose syndrome. But it flew as is (was?) for a season and half before the nose broke.

[RogerGreene]

May be add a washer under front engine mount screws to add a touch more out thrust. Or adjust leadouts a degree or so sweep back. All this to give a little more right yaw. You might notice more pull on the lines, but overheads will have more line tension.

Just a thought
~ Roger

[Joe Yau]

I fly my slightly modified (flapped, larger elevator and solid fuse) FS at about 4.8-5.0 (depends on the condition).  with 60' C>C  .015 lines.  Its a decent plane for learning the pattern.. or practising the 2' bottoms..  just kidding.  I use a ST C.35 on it with a APC 10.5"x4.5 cut down to 10" and has been the best prop so far.  I also use a MA 11"x7 3-blade repitched to 4.25 and cut down to 9.5"  it seems to help the verticle climbs and above 45degrees stuff like OH-8 on a windy day.  I think gut feeling is the key. The Flite Streak does have a "very narrow" window where it flys good at the slower speed. usually if the line tension is good enough to do the RWO you're in the ballpark.

[Steve Helmick]

So does that mean larger or smaller diameter and or larger/smaller pitch in prop size?
I'm thinking a smaller prop speeds up the engine but slows the plane down?
Cheers Phil

Propellers are really "Black Magic". Try some that seem like they might work. Avoid preconceptions as to what won't work. Some of those dagger bladed APC's work just wonderfully. So do some of the wide blade Graupner nylon props, and some of the Thunder Tiger Cyclone props. They're all very different. Wood props are always suspect, but don't overlook the TF "Power Point" props, if they have a size that seems appropriate. If the engine is a bit bogged down, trim the diameter a bit and retest. The XOAR props (and RSM props, which are made by XOAR) are also worth trying.  I have a tough time justifying testing a prop that I cannot replace or otherwise duplicate.  Steve

[phil myers]

Steve, thanks for the reply, but I'm still not sure on the theory of props despite reading over stuff time and again.
I understand a lower pitch will slow things down, but would a smaller diameter have a similar effect?
Thanks for any advice... Phil

[Steve Helmick]

The engine has to be "happy". If it doesn't needle well, it's not! If the engine isn't happy, the model won't be, and they'll contrive to make the pilot unhappy as well.  Steve

[Mark Scarborough]

first rule of prop research,, none of what you think works will neccessarily work!
I have seen a plane go from a 9x5 to a 10 x 4 and fly faster. I have seen narrow blades unload the motor better ( or load depending upon your perspective) and then the plane be much happier.

It truly is a matter of cut and paste, try and fly. Pat and I flew the LA 46 'x on APC 11x4, 11x5, 11.4.5 props, and the plane flew well but getting a steady needle that was consistant was difficult. We switched to the APC 12.25 x 3.75 and it was pretty much accross the board Nirvana. Thats more prop than a lot of ST 46 run, I have seen .51 engines that dont like that much prop but for some reason on the LA 46 its magic. So short story is,, try, fly,, try fly,, until you find the combination that works on YOUR airframe, and YOUR flight speed

[phil myers]

Thanks to steve and Mark for the replys. If I've understood this right, theres only one way to do this and thats to try different sized props until the plane is doing what you want. (My apologies to Kim for hijacking his thread!)
...Phil

[Steve Helmick]

Phil, I want to make it 100% clear that it's not just the size of the prop. It's the size and the brand.

On my .25LA, the 9-4 APC and 9-4 Graupner both worked quite well. But a 9-4 Zinger would not work as well. I'm not sure if there is a 9-4 TF Power Point, but I think it might work ok. I tried the 10-4 TFPP (with some rework), and it worked pretty well. The 10-4 APC worked ok, but the engine seemed overloaded. I still haven't tried the 9.5 x 4.5 APC, but I'd almost bet money that it'd be really good. The Skyray also needs shorter lines than what I've used, but haven't flown it in at least a year. It's too heavy, anyway.  I might drag it out for the next Fun Fly.
  Steve

[john e. holliday]

Phil, to me that is the secret.  You get the plane to fly the way you want it to and that is happiest at.  I started out with the Top Flite 10-4 powere point, which worked great for me.  Tried several others, but, going back to it.  In the 9 inch size it was the 9-5 that worked just as well, but, would slow down a bit in consecutive manuevers it seemed like to me.  This where the fun comes in for some.  Trying different things to see how they work.  Sometimes it works, sometimes it doesn't.  Keep notes.  Have fun,  DOC Holliday

[phil c]

The main thing is to get the right combination of speed, airplane weight and line size so the lines are pulled tight with a leadout angle of about .8in/24in.  If you can get the weight down enough to use .012 lines that will help too.