Mr67Stang

I have had the Weston Magnum on my watch list here in the RCU Market Place for some time now waiting for the right one to show up at the right price. Several used ones popped up RX ready and where local pick up only. Last night someone posted a NIB one that he would ship at what I felt was a good price. At least, I was willing to pay it. I have posted the pictures from the ad. Can someone tell me if this is the early version or the latter MagnumR? I really don't care either way, I will be happy with it.

evan-RCU

Non R version, I have an identical one new in box in my work room along with my 7(?) year old one I still fly...

Mr67Stang

Thank you, I'm sure it will be adequate for me. Since you are familiar with the plane, do you have any tips on the construction? Do I need to reinforce anything? Any common modifications or known issues? Factory ballance point works or is there a better location?

evan-RCU

Make sure the hinges are well attached, maybe even add a couple. The elevator push rod set up is a bit cheap but works. If you do it their way keep an eye on it. Get a better fuel tank, I have a Sullivan in mine and it's worked very well. Get rid of the carbon covering. It is not regular iron on, it's held on by static and will come off in flight. CG... I think it's right but I built mine too many beers ago and don't remember if I set it at the recommended point. There are some posts here about CG. Vic may have better/ more recent memory. If you can't find it I can go measure it.

Mr67Stang

I apreciate the tips. I am concidering assebling this thing and taking it with me on vacation this summer when I go to Seattle and flying it with CP

evan-RCU

There are two here at our field in Charlotte... There are one or two up in Vics field too.

combatpigg

My Feedback: (3)

Stang, nice acquisition! Sessholvlaru got his dialed in pretty good last year [195 mph], I'd ask him about where he balances his. The old threads had complaints about those birds being too nose heavy. I've used Geistware to find the CG of some planes, but it's hard to decide where some lines begin and where some end..if you're off just a little with a swept and tapered wing, you're off by a lot.

Mr67Stang

Thanks CP. I only have about two weeks until I leave for my vacation. I hope to at least sit and have a beer or six with you.

combatpigg

My Feedback: (3)

Sounds good. I think by then there won't be any more water coming out of the sky.....?

MJD

My Feedback: (1)

The rearward CG in the instructions is not "rearward", it is "not as stupid far forward"..

MJD

BiggerDanno

I just madidened mine this weekend with the CG set at 155 mm, that is too nose heavy as the elevator required quite a bit of up trim. I'm going to re-balance with more weight in the rear before the next flight.

BTW, this thing rocks!!
Had a grin ear-to-ear the whole flight.

Less than three minutes the 6 oz tank was dry, might have to go to an 8 oz.

Mr67Stang

Deffinately apreciate the tips!

MJD

My Feedback: (1)

I used a 8 oz Jett slim bubblefree tank and it worked beautifully. Only needed a quick kiss with the Dremel on the former to clear, and bonus you don't need wads of foam.

I did a graphic NP on the Magnum ages ago, and worked out the CG at over 200mm.. but I never went that far. 155 is a starting point though. For reference, if you know the significance of this, the 25% MAC point on the wing is 193mm back from the LE at the fuselage/wing junction.. [:-]

They're fun. Much more fun with wide flat fields so you can take your time on the approach and flare. Dumping them in more confined fields is a challenge.

MJD

summerwind

what's the wing area on this bird?
i'm getting ready to design something smaller and lighter than the Patriot for a next step up into the speed realm............

Mr67Stang

This is perhaps the best peice of information posted yet! Having load planned 100's of military cargo aircraft I know exactly what you mean here. I am suprised that at 155mm or 20% MAC you are happy with it. Does it get twitchy after that?

vicman

My Feedback: (10)

After you drink all of CP's beer you need to bring it over to the Speed Rally on the 26th and meet your Canadian brothers in speed.

No twitchy. But much better take off and landing charactaristics. If you leave it too nose heavy the plane makes a breath taking sink at launch and lands pretty hot. If you get it right you pull out nice and level and can flare nicely for a smooth landing. Be warned though it glides like a brick.
I used a stock Futaba Nicad battery pack stuffed as far back in the fuse as it would fit, yes, I cut a hole and still have .5 oz of lead stuck to the tail. Thats with a SJ.50 on the nose.

What engine are you planning to use?

Mr67Stang

I am taking 4 weeks up in CPville so I wont be back in time for the Speed Rally. For now I have an OS 55ax and a one peice Macs pipe to get warmed up with. I bought an APC 10x7 today for starters as well.

MJD

My Feedback: (1)

155mm isn't 20% MAC, unless the wing's average chord is 775mm (30.5"). 193mm is the distance back from the LE at the fuselage junction, at which the 25% MAC point is located. I'll mark up a top view of the flying surfaces, MAC and all that stuff and post it here soon as I have the chance. The 25% MAC point is significant because almost no matter what the tail volume it should be a conservative starting point for the CG on a conventional layout aircraft.

There are guys overseas flying these things at around the 190mm mark so I was told. Nobody that posts here has ever reported going back that far. No real need, but don't fly at the instructed forward point for sure unless you like ballistic landings.

MJD

BiggerDanno

Mine flies fine at 155, landing was not an issue, even with our short runway. It only slid about 8 feet after touchdown on asphalt.

Since I required about 2 mm of up elevator trim, I'm wondering it I have the aierlon neutral set properly. Since the wing has an upturn at the tips (which at first I thought was a twisted aierlon), I made the neutral point with inside edges even with the wing. This leaves the outer edges below the wing. Maybe I should make the outer edges even instead?

combatpigg

My Feedback: (3)

I think the outboard edges are the most important to line up. No science, just a hunch.

I would think that flying at 20% is wasting some of that extra power that your TNC tach is getting you?

BiggerDanno

LOL, haven't got the tach yet.
I think I'll try lining up the inside edges and see where that puts it trim-wise before re-balancing.

combatpigg

My Feedback: (3)

You know, Weston must have hundreds of these planes flying. So why is there so much controversy over the CG? A nose heavy plane just "feels" heavy in the sticks while it's flying and will zoom towards the canopy when you are in knife edge. If the factory doesn't have their complaint line ringing off the hook, they should if the planes are landing at punishing speeds.
It is amazing to see how well these sell, they have an eye for what works. I think the important thing to success [besides performance] is packaging and getting the word out. I've noticed how some companies make a big initial investment in very expensive advertisement to get the ball rolling, then once the product gains momentum they pull back on the ads just enough to maintain a roll.

BiggerDanno

Perhaps due to the aformentioned goofy wing? I'm sure that when I align the inner edges my trim is going to change. Whether it then requires any elevator trim remains to be seen.

MJD

My Feedback: (1)

As far as looks and the perception of speed, they nailed it. And with their marketing hype. No wonder they sell. And they are fast, just nowhere near as fast as stated.

As to the CG - everyone who has appeared on RCU that I have seen has commented on the nose heavy feel and high landing speeds, and those who have taken the plunge and started moving the CG aft have reported positive results. No diff for me. I have never seen a report of someone moving it so far that it got sensitive, that I recall. The thing is, it's so crazy far forward at the factory forward level that the amount of backstick needed to flare in the glide is ludicrous. Maybe if you fly from flat grass fields with a clear approach from way out, it is not so big a deal. But start adding any challenges to the approach/landing and it can be a nightmare.

When I talked to Weston directly about it on their order/complaint line, they blew it off saying it helped it to groove. Mine grooved fine at 165mm and would flare. In other words I called and registered my thoughts and was essentially ignored. In the same conversation I was also told about the 248mph flight speeds of the factory team models. From my modest exposure to hobby marketing you usually see a very small percentage of feedback at the factory level, unless the thing just doesn't work at all or shows up busted. A lot of people assume that a flashily dressed commercial product must have it;s act togeh

On top of this it is a niche applicaiton product, and I think a lot of people blame themselves with landing troubles on their first or second high speed/highish wing loading model.

MJD

mk1spitfire

Heres a question. Is a nose heavy plane better suited for speed than a tail heavy model?
Or doesn't it matter or just preference.