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  1. #26

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    RE: Something strange happened at the field today

    This is a VERY interesting thread.  Thanks to the OP for posting as I have learnt quite a bit just from reading.  Definitely a wealth of knowledge out there, all one needs to do is post the correct scenario.

    Thank for your replies all

    DaleD

  2. #27
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    RE: Something strange happened at the field today

    the answer you seek is simple ... Chinese
    Contest Director /Turbine pilot/ P-38 Brotherhood/Scratch Builders make their own Destiny

  3. #28
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    RE: Something strange happened at the field today

    I have a new DLE111 that had all four left side cylinder bolts loose from the factory. Luckily I think i've hopefully caught it in time. The very first engine run on the plane was for 5 min, then I let cool and did another easy 5 min run. After this I noticed the leak on the left cylinder gasket. Thinking the obvious I soon discovered each cylinder bolt need a half turn or more. They probably were not much over finger tight. Not having a torque wrench I tightened them best I could with a long Allen key wrench. The engine was still hot too so I think I probably got them good enough.

    Anyway, lesson learned. Check your new engines. The engine now has 5 gal through it and is going strong. I'm wondering though if I should get new bolts and torque them correctly now?
    If you cannot afford to do something right, then be darn sure you can afford to do it wrong.

  4. #29
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    RE: Something strange happened at the field today

    I put a DLE55 on a diet a couple years ago. Shaved a little more than 10% of the engine's weight. The diet included titanium bolts for the jug and crankcase. These were around 3 bucks a bolt as I recall. The long carb bolts were more like 10$ a bolt. Yes a bit pricy but worth the weight savings to me. The 55 has 6 gallons of gas through it, and NP and don't expect any.

    You guys might consider using Ti bolts next time you want to change the DA stock bolts. BTW- if the bolts are aircraft grade there is plenty of strength in the aluminum. Threads are typically rolled, not cut.

    Ti bolts are also anodizable, just like Aluminum...same colors as ally
    Regards,
    MattK
    (Rcmaster199@aol.com)

  5. #30
    Ernie Misner's Avatar
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    RE: Something strange happened at the field today

    Just curious, are the titanium bolts actually lighter an aluminum?

    Thanks,

    Ernie

  6. #31

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    RE: Something strange happened at the field today


    ORIGINAL: MTK

    I put a DLE55 on a diet a couple years ago. Shaved a little more than 10% of the engine's weight. The diet included titanium bolts for the jug and crankcase. These were around 3 bucks a bolt as I recall. The long carb bolts were more like 10$ a bolt. Yes a bit pricy but worth the weight savings to me. The 55 has 6 gallons of gas through it, and NP and don't expect any.

    You guys might consider using Ti bolts next time you want to change the DA stock bolts. BTW- if the bolts are aircraft grade there is plenty of strength in the aluminum. Threads are typically rolled, not cut.

    Ti bolts are also anodizable, just like Aluminum...same colors as ally
    Would you be kind and post a link to the suppplier of them coloured Ti bolts?

    Thanks

    DaleD


  7. #32

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    RE: Something strange happened at the field today

    I'm not sure which "Aircraft grade"aluminium is being refered to?
     
    2024
    6061
    7075?
    All are high strength alloys but none are as strong as steel.
    All are available in ALclad for corrosion resistance but this surface treatment typically reduces the effective tensile area of the component.

    Ti bolts are tougher so they can be loaded and reloaded through more repeat cycles.
    Neither has the UTS or  fatigue life of steel.
    SInc eour two stroke are not hgh compression I'm sure the manufacturer can get away with AL bolts but at a reduced factor of safety.
    I could understand the desire to use these on a 20cc to 30cc engine but on a >100cc i'd really like to understand why.

  8. #33

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    RE: Something strange happened at the field today


    ORIGINAL: Truckracer


    ORIGINAL: dirtyoldman00

    Ive got five DA engines 50's and they all have aluminum bolts and when I orderd spares they sent new aluminum bolts You mess with the bolts youll blow your warranty
    My DA engines are so far out of warranty that it doesn't matter any more what kind of bolts I use!


    Karol
    When inverted always remember that down is up and visa versa

  9. #34
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    RE: Something strange happened at the field today

    7075-T6 low gall aluminum alloy. Make sure the threads are rolled and not cut

    Try Mettec or Pro Bolt for Ti bolts. Prices are higher than a couple years ago, about 4$ a bolt.

    Aluminum is slightly lighter than Titanium; either metal is less than half the weight of steel. But even the best aluminum A/C grade has a UTS of around 70 ksi. Titanium starts at around 120 ksi....fairly close to steel strength, but costs about 6X as much as SS.

    Like I said, cost is not a terrible concern for my application so I buy Ti bolts where applicable
    Regards,
    MattK
    (Rcmaster199@aol.com)

  10. #35

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    RE: Something strange happened at the field today

    You do know that with da, the warty is almost really lifetime... Send in your motor they tear it down tell you what you need and you ONLY pay parts... NO labor!! So you only pay parts an labor... You would be an idiot to not send an engine back to DA... Just sent out a 150 and it cost $10 to ship USPS from Maryland to Arizona....

  11. #36

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    RE: Something strange happened at the field today


    ORIGINAL: matt43

    You do know that with da, the warty is almost really lifetime... Send in your motor they tear it down tell you what you need and you ONLY pay parts... NO labor!! So you only pay parts an labor... You would be an idiot to not send an engine back to DA... Just sent out a 150 and it cost $10 to ship USPS from Maryland to Arizona....
    Yes, I know they take care of things but I'll still stay with my steel bolts. And I have sent engines back with the steel bolts in place .... they came back with the pretty red aluminum replacements! Frankly I haven't needed much service lately so its all pretty much a non issue to me. I still prefer to take care of minor issues at home.

  12. #37

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    RE: Something strange happened at the field today


    ORIGINAL: MTK

    7075-T6 low gall aluminum alloy. Make sure the threads are rolled and not cut

    Try Mettec or Pro Bolt for Ti bolts. Prices are higher than a couple years ago, about 4$ a bolt.

    Aluminum is slightly lighter than Titanium; either metal is less than half the weight of steel. But even the best aluminum A/C grade has a UTS of around 70 ksi. Titanium starts at around 120 ksi....fairly close to steel strength, but costs about 6X as much as SS.

    Like I said, cost is not a terrible concern for my application so I buy Ti bolts where applicable
    Interesting thanks. I do use Pro Bolt ti bolts and some aluminium bolts on my Mtb and Road bicycles in non critical areas (like chain ring bolts)
    If 7075 to T6 hardness is employed then that would offer some comfort. Howver , those bolts are fit once and toss when removed in high stress areas.
    The Ti are a better option I agree.


  13. #38
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    RE: Something strange happened at the field today

    I make it a point never to stand in line with the prop arc, now best move back behind the jug as well! Can't you just see a jug go blasting off while you're flying and suddenly you would be in a dead stick situation with a drastically tail heavy craft..... For safety a tiny parachute could be attatched to each jug.

  14. #39
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    RE: Something strange happened at the field today

    Here's some pics of a DA blowing a jug with aluminum bolts. DA made it all better. The kid was flying. I got to repair the airframe damage.

    This aircraft did a deadstick and couldn't make it over a perimeter fence.

    Bob
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    Bob
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  15. #40

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    RE: Something strange happened at the field today

    Anodizing metal weakens it! Could be a factor.

  16. #41

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    RE: Something strange happened at the field today

    The angle on the back of the cylinder mounting flange is draft for the casting process. The proper way to make a bolted joint would be to spotface the back side of the flange so that the bolt head seats against a flat surface.

    One advantage that I have noticed with the aluminum bolts. I have seen a DA 100 take a pretty hard crash that broke the aluminum bolts on both sides, and it was repairable. With steel bolts you typically break the cylinder or crankcase mounting flanges in that type of crash and throw the engine away.

  17. #42

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    RE: Something strange happened at the field today


    ORIGINAL: Ernie Misner

    I make it a point never to stand in line with the prop arc, now best move back behind the jug as well! Can't you just see a jug go blasting off while you're flying and suddenly you would be in a dead stick situation with a drastically tail heavy craft..... For safety a tiny parachute could be attatched to each jug.
    Jugs removing themselves from the engine happen from time to time in Fuel (Nitro) Harley drag racing. Not a pretty sight and there have been injuries from this.

  18. #43

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    RE: Something strange happened at the field today


    ORIGINAL: gsmarino2000

    The angle on the back of the cylinder mounting flange is draft for the casting process. The proper way to make a bolted joint would be to spotface the back side of the flange so that the bolt head seats against a flat surface.

    One advantage that I have noticed with the aluminum bolts. I have seen a DA 100 take a pretty hard crash that broke the aluminum bolts on both sides, and it was repairable. With steel bolts you typically break the cylinder or crankcase mounting flanges in that type of crash and throw the engine away.
    So why is the spot-facing NOT done? Then shot blasted to prevent cracks.
    Imagination is far more important than knowledge. Albert Einstein.

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  19. #44

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    RE: Something strange happened at the field today

    Forget the bolts, replaceable toy airplanes, GET THAT KID AWAY FROM THAT PROP AND ALL PROPS!

    MTY

  20. #45

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    RE: Something strange happened at the field today

    Don,t get too excited....the KID is just trying to imitate his Da Da. HMmm...click the switch and turn prop...just like DAD!!!!!!!!!!!
    Imagination is far more important than knowledge. Albert Einstein.

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  21. #46

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    RE: Something strange happened at the field today

    I sense that KID is the pilot of the plane and not your average garden variety kid. Probably knows more about planes than many adults.

  22. #47
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    RE: Something strange happened at the field today

    It's funny how a picture gets people excited. And yes, Truckracer, you are correct in your assumption. He's a teenager and has been flying for a number of years. Dad can't fly as good as him. Good kid too. Has has feet on the ground. His first love is fishing, though.

    Bob
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  23. #48
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    RE: Something strange happened at the field today

    That's the pit crew... Doesn't look like he's trying to start the beast, just checking the prop bolt torque... Gotta learn somehow!
    Build well! Ben
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  24. #49
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    RE: Something strange happened at the field today

    One little thing about Titanium, probablly not so much of a factor with R/C engines, it's fairly far up on the cathodic side of the galvanic series of metals, and in direct contact with Alumimimum will cause corrosion. Used to have to take special precautions on the "old F-14 where the rest of the airplane attached to the Ti wing center beam structure, which was all Titanium.
    In God I trust.
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  25. #50


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