Tech 03: Spring spacing, Roll Stiffness and Transverse Weight Transfer

Transcription

1 Tech 03: Sping pacing, Ro Stine and Tanvee Weight Tane 1 P age By Doc Hathaway, H&S Pototype and Deign, LLC. Undetanding how you choice o ping type, ping tine, ping pacement and ping ange inuence the ont and ea o tine and the o tine ditibution i impotant to undetanding how the weight i ditibuted to the tie when the ace ca i coneing. In thi tutoia we wi wok pimaiy with heping you undetand how o tine i detemined and how you choice o the above mentioned vaiabe aect it vaue. Jut a the ping act to uppot the ace ca weight and conto the vetica chai motion, they ao wok to conto the amount o o the ace ca chai ha when coneing. Thi eitance to chai o oeed by the ping i caed o tine. In addition to the o tine, the ont and ea o cente height ao detemine how each o the upenion tane the coneing oce, the weight tane and how much o the chai take on duing coneing. Tech 01- Sping, Shock and you Supenion which wa poted eaie i a eeence o thi Tech eion. A quick oveview o that mateia i incuded to aue you have coect upenion vaue with which to wok. The teminoogy Thee ae two pimay ange that goven how ace ca tane weight duing acing maneuve. The it i the o ange which i the ange, ide-to-ide, the ca eek a the tun i enteed and a the ca poceed though the tun. I thee i a o ange, thee MUST be a cente o that otation to occu about; that deine the o cente. Thee ae two o cente on a ace ca, one at the ont upenion and one at the ea upenion. I a ine i dawn connecting the ont o cente to the ea o cente, thi deine the axi about which the chai want to o; thi i caed the o axi. The atio o the ont upenion o tine to the ea upenion o tine i caed the o tine ditibution; when woked to incude the o cente it i eeed to a o coupe ditibution. The econd ange i the pitch ange which i the ange, ont to ea, a the ca i baked o acceeated. In a Supemodiied, pitch ange may be inuenced by, a much a anything, aeodynamic. Jut a in o thee i a o cente and o tine, in pitch thee i a pitch cente, a ping cente and thee i pitch tine. Pitch behavio wi be et to a utue atice. Ou dicuion wi incude the above mentioned tem a we a a dicuion o the o the point on the ame to which the ping tane the whee oad. The ping bae i typicay naowe than the tack width, om ide-to-ide, a the ping ae ocated inide the tie ocation. The ping bae may ao be hote o onge than the whee bae a the pickup point on the ame o the whee oad may be owad o behind the axe centeine. A you wi ee, the ping pacing, o pan, pay a big oe in the o and pitch tine detemination.

2 Sping Spacing o pan Thee ae thee impotant thing to conide in detemining the o tine on the upenion. The it i the ping ate o the ping, the econd i the motion atio o the ping and the thid i the ping pacing. The it to be examined wi be a impe taight axe with ping o equa vaue and ping in a vetica oientation. Sping pan () Tack width (t) Figue 1: Soid axe upenion with tack width (t) and ping pacing () The omua o detemining o tine om the ont upenion hown in Figue 1 above, with equa ping in the ont i a hown in Equation 1. I o exampe the ca i et up with a pai o 500 b/in ping (K) and ha a ping pan () at the chai o 48 inche the o tine ( ) i a hown beow. Equation 1 = K = K A hown in Equation 1, o tine i the toque on the chai to caue a cetain o ange. Ro tine theeoe ha a vaue in t-b, a in toque, o the ange poduced in degee, o tb/, to a 40 inch ping pan a hown in Figue and cacuated beow. 48*48 t b * Sping pan () Tack width (t) Figue : Soid axe upenion with tack width (t) and ping pacing () P age

3 To get the ame o tine with a 40 inch ping pan a with a 48 inch ping pan it woud equie inceaing the ping tine to 70 b/in. = K Ro Stine and ping cente with dieent ping ate 40*40 t b = K * With that aid, many ace ca do not ue the ame ping on the et and ight ide. To anayze thi ituation popey, you need to ind the ping cente. The ping cente i that point between the ping whee you coud tand on the ame and the ame woud move down equay on each ide. A you tien a ping you move the ping cente towad the tie ping. A the ping cente move o doe the o cente. Think about it thi way: i I put a pipe in pace o the et ont ping, when I puh the ame down it o aound the LF ping mount. That i now the o cente poition et to ight with the panhad ba etabihing the height o the o cente. So i you oten the RF ping you make that cone ote, which uuay give that cone moe taction AND you move the o cente to the et towad the tie ping. Both the o cente moving et and the ote ping give the RF moe tave which then typicay give the ont moe taction which in tun ooen the ca up. By the way, otening the ight ont on a ace ca with a high toque engine wi ooen the ca up on the thotte a we, paty due to the tanvee weight tane, which we wi dicu ate in thi atice. To ind the ping cente, et to ight, you ae going to ue the equation beow to identiy how a o cente you ping cente i om the cente o you ping mount. 40*40 t b * Sping cente oet (X) K K X K K Equation ping pan. K K X. 67inche K K We have now ound the ping cente to be.67 inche towad the tie ping om the cente o the chai mount. By taking out 100 b/in o ping ate om the et ont we oweed the o tine and moved the ping cente to the ight. 3 P age

4 Now you can cacuate o tine uing Equation 3. In ou exampe / = 48/ = 4 inch and X =.67 o (/+X) = 6.67 inch and (/ X) = 1.33 inch. The tota o 6.67 pu 1.33 = 48 inche, which i the pan. K X X K X X t b deg Equation 3 Now you know the tue toy the ca we jut did ha the ping cente at 6.67 inche om the et ping mount and ha a ont o tine o 745 t-b/ Having un yet!! In thi exampe, umption you ca ha a ight ont with the coi-ove incined 0 degee to the cente which give you ace ca a ping pan that i mae. Due to the motion atio o the ping and chai, the ping ate, uppoting the chai, actuay i ote. Sping pan () Tack width (t) Figue 3: Soid ont axe with the RF incined towad the cente ANGLE ( ) Coine( ) Coine ANGLE ( ) Coine( ) Coine Tabe 1: the eect o ange on ping ate Sping ate ame Coine Sping ate Equation 4 Sping ateame b / in 4 P age

5 that to get the ange we moved the RF coi-ove in 3 inche. Now you have a ping pan o 45 inche. Uing equation and equation 3 with a 400 b/in et ont ping the o tine i cacuated. K K X 1. 07inche K K X 3.57 X t b deg Thi indicate a eduction in ont o tine o 17% (745 to 617), which i a igniicant change. You ao moved the ping cente coe to the LF becaue you otened the RF and thi ite poduce moe o ange. Now, jut to conue you uthe, ont end a hown in Figue 4. Sping pan () 5 P age Tack Width (t) Figue 4: A impe ocke am (cantieve) upenion The o tine i cacuated uing the ping pacing jut a beoe. Some buide want to ue a dieent ength am on the hoizonta pat o the cantieve than on the vetica pat me why becaue it hut you hock peed a dicued in Tech 01 that wa poted on thi ite). buide Joe ue a owe am ength o 1 inche and a vetica am (connected to the hock) o 10 inche. By the time Joe put it a togethe with the maximum width ue he now ony ha a ping pan o 9 inche becaue he ha 6 inche o tie pu inche o ceaance on each ide and 4 inche o ocke ength. Then Joe put a motion atio o 10/1 = 0.83:1. Reca now to get the ping atio the motion atio i mutipied by ite o the ping atio i 0.83 x 0.83 o 0.689:1. Theeoe, due to motion atio, a 1000 b/in ping i acting a a 689 b/in ping. Note i the am wee the ame ength and the ping act taight to the am, the motion atio i 1:1.

6 Fo ictitiou Joe, hi ca ha a o tine o 97 t-b/degee, a hown beow, even though we bumped the ping ate to a 700 b/in ate. So thi ca ha a high ping ate, giving you a high whee ate with a ow ont o tine. We wi examine thi uthe a we tak about tanvee weight tane. = K t b might be a deign whee you woud conide an anti- o ba to add to the o tine i deied. I hope thi dicuion thu a ha given you ome inight into ping ate, ping pacing and o tine. Rea Ro Stine, Tota Ro Stine and Ro Stine ditibution: A the wok and undetanding we have done thu a o the ont upenion appie to the ea upenion a we. In mot cae in the ea the geatet pan you can achieve i about 48 to 50 inche due to the width o the tie and the ISMA, o othe govening body, width etiction. To undetand the compete pictue you mut ook at tota o tine and o tine ditibution. e o dieent coniguation. Cae 1: Thi cae ue the peviouy examined ca with a 48 inch ping pan with a 400 b/in ping in the et ont and a 500 b/in ping in the ight ont. The ont o tine wa cacuated, a hown beow, to be 745 t-b/ t b deg -b/ = K 48* 48 t b * The tota o tine i the addition o the ont and ea o tine. The tota i then 745 pu 417 o 116 t-b/ The pecentage o the o tine that i in the ont i 745/116 = 64%. Shown beow ae the cacuation. 6 P age tota t b / deg 745 % F % 116 tota Cae : I the ame ea upenion i ued but we compae it now to ou ocke am (cantieve) upenion with the owe o tine a hown beow.

7 tota t b / deg 97 % F % 714 tota Thi how a ont o tine popotion eduction o about 30% (64 v. 41%). The highe the pecentage o ont o tine the moe noe aeodynamic you wi pobaby need to tun it in the cente, depending on you weight ditibution and a numbe o othe acto. The next atice I pan to wite wi adde weight ditibution in a tun which wi ue the o tine a a key eement. Let now ook at how o tine ditibution aect acceeation o the tun. Tanvee weight tane = K t b Tanvee weight tane i not anything a ancy a it may ound. A ca which have the engine mounted to the ame and ping epaating the dive axe and the ame wi have tanvee weight tane becaue the dive hat appie toque to dive axe which i ony eited by the ping and the tie on the tack. The quick iutation how the dive hat toque (T d ) twiting the ea end and the eaction toque (T ) eiting that motion, Figue 5. Figue 5: Tanvee ate mode ace ca exampe Tanvee weight tane occu becaue the divehat toque (Td) eact between the amemounted engine and the dive axe. The axe ha to eit the toque at the tie oot pint. It i impotant to eaize that tanvee weight tane add co weight duing acceeation and emove co weight duing deceeation. The co weight change duing deceeation i much e than duing acceeation becaue the ony dive hat toque i that due to deceeating the ca. The co weight that i added duing acceeation depend on the o tine ditibution, the engine toque and the ea tack width. On a Supemodiied, dive hat toque and engine 7 P age

8 toque ae the ame o the omua i a hown in Equation 5, with W tanvee indicating the tanvee weight tane. Let ue an engine with 650 t-b o toque a an exampe and compae the two upenion ytem o Cae 1 and Cae, above. Fo Cae 1: W tanvee Tengine tack width tota Equation W tanvee 86 b 58in 116 By the way thi i why dag ace ca away it the et ont it a the tanvee weight come o the et ont and add to the ight ont. The othe thing i that a dag ace ca aunche in it gea which mutipe the engine toque by about 3 time o it ha a high tanvee weight tane une you ue amot no ont o tine. In eaity with the oet o the cente ection, the weight added to the et ea and ight ont duing acceeation can be a high a 3 time that cacuated. becaue o the common ping pit that ae ued ont and ea aect how much i added to the et ea and how much i emoved om the ight ea. At two time it make it about 17 b. o tanvee weight. The 17 b. i added to the et ea and to the ight ont adding 344 b. to the co. It emove the ame amount om the et ont and the ight ea. I the ca wa caed at 50% co the impe numbe woud how it going up to 68% duing acceeation, which I ee to a dynamic wedge. Fo Cae : W tanvee 55 b 58in 714 Fo Cae, uing ou ame mutipie due to cente ection oet and ping pit we added 110 b. to the et ea and ight ont, a tota o 0 b. to the co. I the ca wa caed at 50% co the impe numbe woud how it going up to 6% duing acceeation. So the Cae 1 ace ca i mot ikey to be tighte in the apex due to the highe ont o tine and tend to be tighte o becaue o the inceaed tanvee weight tane which gave it a highe co weight when acceeating out o the tun. The Cae ace ca i ee in the apex and ee o the cone. It i obviou you can change the ont o tine numbe and the tanvee weight tane numbe by adding an anti-o ba. I it i added to the ont it inceae the o tine o the ont upenion and inceae the dynamic wedge, which i the inceae in co due to engine toque. 8 P age

9 In ummay, with upenion ma change can yied big eut. In a utue atice I wi how how o tine and o cente can be ued to etabih a baic et-up o you ace ca. Dicaime I hope thi dicuion hep with you undetanding o how ping poitioning and o tine aect you ace ca handing. Thi i povided a inomation to ISMA membe and i not caimed to be ued a ecommendation o deign o etup. I have had two equet o inomation and I wi be woking on thoe atice in the utue. One equet i o inomation egading ea tee. The econd equet i egading aeo tubing and it beneit othe than heping empty you waet. I you et thi atice wa inomative, o you want to dicu it uthe, dop me a ine at Richad@HSDeignandPototype o [email protected]. I you did not ike the atice I obviouy woud pee you keep it to youe (ony kidding). I you have othe aea you woud ike me to wite on peae contact me at my emai adde. I woud ike to hea om you. My pan i to do ome moe in upenion, teeing and poiby one on Aeodynamic. 9 P age