BaldEagel

Be careful when buying second hand equipment, the second hand one I bought was not what was advertised, servo's supposedly high end and flaps where supposed to have an 8411, on it, turned out to be DS821 on everything except flaps which had a JR ES579, the wheel braks did not work very well and on diss-assemble found that the wheel brake bearings where missing, just a heads up to inspect carefully when you receive the airframe.

Mike

Heat1960

I am setting up aileron reflex on my JR9303 for my sprint and wondering if anyone can advise how much aileron up they are going with(degrees and/or measurement) Also are you only assigning reflex on full flaps or some on half flaps etc. What are most using as a measurement for half flaps and full flaps. Right now I believe I have about 35-40 for middle setting and about 75-80 for full.
Thanks.

Cal.

Dave Wilshere

Cal

Use CROW only on Full Flap, 3/8- 1/2" would be fine.
You degrees? 20-30 for take off and for Landing if you can get 80-85 then that's even better

Dave

Heat1960

Dave, perfect and thanks for the info.

Cal.

BaldEagel

Rigged the re-covered Sprint for the fitst time since I started, as it was a nice day I took it outside and took a few pics.

Mike

MAJOR SPLAT

Awesome job

Regards

Mick

Xairflyer

My Feedback: (1)

Looks great Mike

BaldEagel

Thanks chaps, I will take a video when it flies so we can see how bright the lights are.

Mike

VF84sluggo

My Feedback: (55)

Is a P-70 strong enough for this jet? Just wondering, since this jet is a little bigger and heavier than the Intro.

Dave Wilshere

The Sprint will fly fine on a P-70, top speed is lower on the Sprint anyway, because of the wider fuselage, but it will fly fine with 17-18lb thrust.

Dw

VF84sluggo

My Feedback: (55)

Ok, thanks Dave. It does make sense that the Sprint would be a little slower, for the reasons you mention. That's why I must admit I scratched my head a bit when, in the Sprint kit description on the BoomerangJets website, I read this:

"Not only is the top speed when pushed, higher than that of the Intro, but the flying characteristics are, if anything, even better."

Interesting. Surely for this to be true it must require a more powerful turbine...a P-80 perhaps?

Dave Wilshere

I think the wing section might be thinner?! I'd need to look at my original Intro. But most people put MW54/P60's in the Intro...

Dave

Turbinac

I have to put in my two cents worth, as the designer of the Sprint.

The reason the Sprint is faster than the old Intro is not due to the wing, as it is virtually the same wing design as was on the Intro.
It's mostly due to the much easier transit of the airflow through the fuselage. The Intro was originally designed some years ago for the smaller and older turbines such as the Wren MW54 or the JetCat P60, which needed less air than the modern small turbines which now put out more thrust. On the Intro, the speed was restricted by the small intakes and the big air exit at the back of the fuselage, which created a suction effect that held back the speed, effectively sucking air in at the back.

But on the Sprint, I increased the sidewall height of the fuselage in order to put in relatively huge air intakes compared with the Intro. This allowed me to also increase the width of the fus. to take a larger turbine if it was wanted, but much to my satisfaction it also increased the speed even with a similar small turbine as used previously. I discussed this with a designer of UAVs and we agreed that it would work, so I tried it and it does!

As with all my Boomerang designs, I and my friends fly the pants off my designs before they are ever kitted. That's why they fly like they do. With every design, several changes usually crop up on the way, and the design gets refined to do what I want it to. This was the case with the Sprint.

The Sprint is a modestly priced, good flying "every day flyer" or "trainer" jet, as easy to fly as it's possible for a jet to be, and can be flown as a nippy and aerobatic, but gentle trainer on 12.5 Lbs to a semi "hot rod" on 22 Lbs of thrust without fear, with a very wide speed envelope and as free of vices as it can be.

Alan

VF84sluggo

My Feedback: (55)

Great info Alan! That all makes sense. I was just having reservations about a Sprint being underpowered with a P-70 when compared to a P-70 Intro, as the Sprint is a bit bigger and heavier. I didn't think about the aerodynamic offsets and improvements.

BTW, it was nice to speak with you the other day via phone/Trish/Skype...thanks for all the help!!

Randy

ricardinho

o flew about 200 flights with a p70 and i cant complain at all. about 160 mph on a downwind pass... i think the airframe is limited to go much faster .. the bigger engines will give you maybe faster T/0 AND BETTER VERTICLE BUT AS FAR AS SPEED NOT MUCH MORE..... MY OPINION TO HAVE A NICE LIGHT SPRINT THE P70 IS PERFECT MATCH.....

VF84sluggo

My Feedback: (55)

Holy smokes! That's certainly enough speed for me. But a big vertical is nice, so I wonder if I'd notice less performance with a Sprint...takeoff performance, as well.

Consider this: I have the JetTech 88 oz tank in my Intro. I can fly for 5 or 6 minutes, make an approach or two, and still have at least a third of a tank left, maybe half. So, if I use this size tank in a Sprint, I would be saving a fair amount of fuel weight, initally any way, and may see as peppy performance with a P-70/88 oz fuel as compared to a P-80 with a 125 oz tank.

Xairflyer

My Feedback: (1)

The sprint needs the bigger turbines to get it's benefit, P60 Intro is better than a P60 Sprint.
P70 will suit it well.

ricardinho

I WOULD USE THE JETTECK 125 OZ IF YOUR USING THE P80 OR P120SX. I USED THE SPLIT TANK JETTECH WITH THE P70.. I GOT 10 MINUTE PLUS PLENTY LEFT OVER...

skaap2k

I had a bit of a "Ooopsy" on the weekend.... turns out that if you manage to catch a wheel on an electric fence, the plane doesn't win! - Nor did the fence though, so it must be a draw!
Anyhow.. Can anyone tell me what covering the Military scheme sprint uses? in particular, the silver colour?

Thanks!
Rob

Turbinac

Have you asked Patricia if she has some?

Here are all the Sprint colours used and the Oracover (Profilm) numbers;-

#21-023 Ferrari red
#21-010 White
#21-091 Silver
#21-030 Cub yellow
#21-050 Blue
#21-060 Orange
#21-011 Grey
#21-071 Black

Alan

skaap2k

I didnt think of that

Thanks Alan - I emailed her earlier and she does have some

Rgds,
Rob

rcjetn

My Feedback: (2)

I posted this before, but it bears repeating: The new DuBro 80 oz tank drops right into the Sprint. Costs about $25 or so. The new 100 oz would fit easily with just a little (maybe 1/4") grinding of the formers on either side, but check the measurements yourself. I'm using the 80 oz in my Sprint with a P-120 turned down to 20 pounds. It would be great for the P-70, IMO. Beats the prices of the kevlar ($135-$165). Plus, since these DuBro tanks are not tall, there may be room for a small smoke tank and pump/battery on the top of the DuBro. That would put the smoke equipment near the CG. Haven't tried it myself, though.

Jack

Xairflyer

My Feedback: (1)

Does this mean we wont see the Sprint at Offaly Jets next weekend

skaap2k

The sprint is nearly ready to go again, just waiting on a couple parts which I should have tomorrow... Viperjet arriving tomorrow too!

I've now also removed the electric fence debris from the sprint ... not sure which came off worse!!!

chris1971

I just finished the install of a new Kingtech K-80 in my Sprint after my P-80 destroyed itself last fall. I have to rebalance it and I will be back into the Kero burning business! Do you guys balance the Sprint inverted or right side up? Normal procedure with a low wing is to do it inverted but there are no guidelines in the manual.


Chris