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flyvulcan

Lightning Bug rebuild

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Have you looked at the fitment of the injected Rotax? I can see this engine becoming more popular in the future and perhaps the phasing out of the ULS......

 

 

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Yes, the iS was considered but with the substantial price differential over the ULS, we went for the cheaper option (for now).

 

Of course, being experimental category, the kit builder can put whatever he wants in the Bug so the iS is always an option for the Bug owner. However, we are aiming to provide the best possible reliable performance for the lowest price, so we are starting with the ULS.

 

 

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The new cowl cheeks have been fabricated from carbon. They have been clecoed in place on the cowling and doors have been cut into them to facilitate working on and removal of the engine.

 

Here are some pics.

 

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Due to the slightly higher positioning of the prop shaft with the Rotax installation combined with the new spinner that we have to suit the installation, we shall need to build up the upper surface of the cowling where it meets the spinner to fair it all in nicely. This is only a minor job so won't take long.

 

 

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The custom exhaust system has been squeezed in and is now fully welded up. Lanny has done a really good job to fit it all in.

 

image.jpg.588d2bdc46f0798bcda01a543ebd0f55.jpg

 

image.jpg.222a3c6432df0c8924bd29c484d51272.jpg

 

 

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Well it's certainly got a fast look to it. Good to see the progress keep up the good work.

 

 

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Thanks SDQDI. It certainly looks fast. We hope that translates into going fast as well!

 

The top shot posted by Speeddog7 (a big welcome to the forum for the guy doing all the hard work) shows the lines really nicely. The new cowl cheeks should have minimal impact on performance over the original configuration. Hopefully the slower turning Rotax with a larger diameter prop can give as much or better performance as the original AMW. Time will tell, but we'll keep everyone posted here on our results, good or bad (hopefully the former!).

 

 

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Lanny has now removed the engine to do a final check of things before the engine goes back in for good (hopefully!). He has hooked up a number of the systems, i.e. The nosegear retract system, exhaust etc..

 

The nosegear retracts and extends as it should.

 

image.jpg.fe26e12d994c28f04ae90da2f27c8696.jpg

 

And the exhaust has been squeezed in nicely.

 

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We are currently sourcing a custom radiator for the installation, plus resolving a few other small issues. Hopefully, we aren't too far away from that first engine run.

 

 

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Look on ebay for curved sports bike radiators such as Suzuki GSXR, Kawasaki Ninja, Honda CBR, Yamaha R6 R1

 

If they are too big look at using a couple of the 450 motocross radiators., YZF450, CRF450, KXF450, RMZ450

 

Question; If you rivet the carbon fibre side poddy things on with aluminium rivets will there be a corrosion problem? I have heard they don't like each other?

 

 

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Hi Bex,

 

The cowl cheeks will be glassed to the existing cowling, not riveted so no corrosion problems.

 

As for the radiator, on the Bug, the radiator is enclosed in a duct. We will be modifying the setup to allow the radiator to be slotted in to the duct to facilitate easy installation and removal. Consequently, we need the radiator to be of a specific size and with specific layout for the inlets/outlets.

 

 

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A closer inspection of the current radiator has determined that it should be serviceable for a while at least so we will use it for initial testing. We will need to see how it copes with the demands of cooling the Rotax 912ULS in place of the AMW808.

 

Lanny has the engine back in and the latest puzzle to solve is that at the base of the engine is an oil system fitting that I believe is a return line from the engine to the tank (I could be wrong on that but Lanny knows what it's for). This fitting needs to sit lower than the structural keel so Lanny has cut a small slot in the keel. We now have to work out how to run the line from inside the wheelwell, out to the oil tank. Lanny will be sorting that problem today.

 

The new custom prop has been trial fitted. We have increased the prop diameter from the original 54" diameter to 62" on the new prop. We have also increased the pitch from 88" to 93". I can hear your gasps already! However, we will need 93" pitch to get 200 knots with the Rotax engine (yeah, we're probably dreaming!). 93" pitch will have a pretty well stalled prop in the static situation. Static thrust is anticipated to only be in the vicinity of 100lbs and up to around 200lbs at 50 knots. It then improves as the aircraft speeds up. It is estimated by the prop manufacturer that best climb speed will be around 120kias. Prop clearance is only 6.25" but Lanny moved the nosegear strut attach point to a lower position and this has stiffened up the nosegear spring appreciably. Lanny has bounced all his weight on the nosegear and it gives around 2" so hopefully we have adequate ground clearance with the prop. If I post photos of a broken prop after the first test flight, we will know that we were wrong :-(

 

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image.jpg.177253bc96db2916c166af94728c8f18.jpg

 

 

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Thanks Topaz and welcome to these predominantly Aussie forums. Between this site and HBA, I'm fairly busy!

 

As for progress on the test bed Bug, Lanny has plumbed the hydraulic lines for the retractable nosegear through the firewall into the cockpit. He now needs to mount the hand pump lever in an appropriate location in the cockpit. For the production kit, we will look at using an electric linear actuator with a redundant mechanical linkage to provide emergency extension in the event of an electrical or actuator failure, rather than the hydraulic cylinder that we are using on our test bed aircraft.

 

A custom radiator will be arriving this Friday which Lanny will mount and plumb into the system. All the oil cooler fittings arrived recently and that will also be mounted and plumbed over the next week or so.

 

So hopefully in around 2 weeks, I will have more photos of the engine bay with all accessories in place. First flight should then be not too far away.

 

 

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Thanks! It's a sleepless night here in California, and on the suggestion of Head in the Clouds, I thought I'd check out this forum. Looks like a great place. 020_yes.gif.58d361886eb042a872e78a875908e414.gif

 

I remember the Lightning Bug being covered in Sport Aviation back in the day. IIRC, there was an issue with the prototype on the cover. It's great to see you guys bringing this one back to life!

 

 

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Thanks! It's a sleepless night here in California, and on the suggestion of Head in the Clouds, I thought I'd check out this forum. Looks like a great place. 020_yes.gif.58d361886eb042a872e78a875908e414.gif

Hey, welcome Topaz! Not sure whether Oz will help your sleeplessness but ...

 

Nice work on the Bug Dave!

 

 

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Thanks Speeddog,

 

I woke up this morning to find the photos of your weekend work from Lanny. Great progress! You've done an outstanding job on the cowl cheeks and gear fairings. That Bug looks so good!

 

I really hope I get to see it in 4 weeks. If you can't make Sun'n'fun, I shall do my best to visit the Bug at home. I drop the family at Orlando Airport at lunchtime on the 23rd but have to leave from Miami on the 27th, so am tossing up the (very) long drive versus the not much different fly/drive option.

 

Regardless, I hope I get the chance to meet you while I'm in the US.

 

Cheers,

 

Dave

 

 

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